Momentum
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LESSON 4 The definition and S.I. unit of momentum Phenomenum A bullet travels at very high velocity A lorry which has a large mass
The value of momentum Large
The Principle Of Conservation Of Momentum The Principle of conservation of momentum states that “ The total momemtum of a system is always fixed if there is no external force acting on the system” or “ In any collision or interaction between two or more objects in an isolated system , the total momemtum of the system will remain constant ; that is the total momemtum before collision will be equal to the total momemtum after the collision”
Large
Conclusion : Momentum of an object is defined as the product of its .………………. and…………… or momentum = mass x velocity p =mv The S.I . units of momemtum is kgms-1 or Ns
Types of collision There are two types of collision , that is (i) Inelastic collision (ii) Elastic collision
Momentum is a vector quantity. Example 1
Inelastic collision
A bullet of mass 0.01k g moves with a velocity 200 m s-1. What is the momemtum of the bullet?
In inelastic collision , after two objects moving with their respective velocities do collide, they stick together and move with a common velocity.
Solution
Example 2 A trolley of mass 1.5 kg moves with a velocity 4 ms-1 hits a wall and rebounds along the initial direction with a velocity 3 ms-1 .Calculate (i) The initial momentum (ii) The final momentum (iii) The change of momentum
Based on The Principle Of Conservation Of Momentum, The total momemtum = momemtum before collision
Solution
= = 24
The total after collision
Example 3
Example 5 A trolley of mass trolley 2 kg and moving with a velocity 0.6 ms-1 and collides with a stationary trolley with a mass 1kg . After collision the trolley of mass 2kg and moving with a velocity 0.2 ms-1. What is the velocity of the trolley of mass 1 kg after collision?
A trolley of mass 1 kg and moving with a velocity of 6 ms-1 collides with a stationary trolley with a mass 3 kg . After collision they stick together with a common velocity. What is their common velocity? Solution
Solution
Example 4 A trolley of mass trolley M kg and moving with a velocity 4 ms-1 and collides with a trolley of mass 1 kg and moving in opposite direction with a velocity 2 ms-1 . After collision they stick together with a common velocity 2 ms-1. What is the value of M?
Example 6
Solution
Elastic collision
Based on the figure above, what is the (a) value of x (b) direction of motion of the ball with a mass 2 kg after collision
In elastic collision , after two objects moving with their respective velocities do collide, those two objects will separate and move with different velocities.
Solution
Explosion
Based on The Principle Of Conservation Of Momentum, The total momemtum = momemtum before collision
The total after collision
In explosion, two objects are initially at rest and after explosion those two
= 25
objects will separate and move in opposite directions. Based on The Principle Of Conservation Of Momentum, The total momemtum = momemtum before explosion explosion
The total after
with a common velocity Total amount of kinetic energy is not conserved
= =
with different velocities Total amount of kinetic energy is conserved
The Applications of the Principle of Conservation of Momentum in rockets or jet engines .
Example 7 A bullet of mass 0.05 kg is shot out from a gun of mass 1.5 kg. If the recoil velocity of the gun is 2 ms-1,what is the velocity of the bullet ?
Rocket Engine
Solution Example 8 A boy of mass 60 kg and a girl of mass 40 kg stand facing each other on a skating rink. The girl pushes the boy and he moves backwards at 2 ms-1 . What is the girl’s velocity?
Jet Engine
Solution
Similarities and Differences between Inelastic Collision and Elastic Collision
A rocket engine carries its fuel with it and can work in space as well as in atmosphere. Two fuels, such as liquid hydrogen and liquid oxygen burn together explosively and force the gases produced out of the rocket nozzle in high speed and hence produces downwards momemtum. Following the principle of Conservation of Momemtum, the rocket will propel upwards with a momemtum that is equal to its previous momemtum because momemtum is conserved.
Similarities Total momemtum is conserved Total energy is conserved Total mass is conserved Differences Inelastic collision Both objects stick together after collision and move
Elastic collision Both objects don’t stick together after collision and move 26
A jet engine uses the same principle of momemtum conservation as the rocket engine except that it takes in air to burn the fuel.So a jet engine will only work in the atmosfera. In the jet engine, air is sucked into the jet engine to be compressed and is heated up in the compressor. The compressed air is then mixed with fuel which is sprayed so that it starts to burn. The exhaust chamber emits exhaust gases with a high velocity. This results in a momemtum of equal magnitude but of opposite direction which moves the aeroplane forward.
1
Which of the following is the units of momemtum? A C
2
kg ms-2 kg-1s-2
0.625 kg ms-1 16 kg ms-1 D -1 40000 kg ms
B 4 kg ms-1 850 kg ms-1
A ball of mass 0.5 kg hits the wall with a velocity of 4 ms-1 and bounches back with a velocity of 3 ms-1. What is the magnitude of the change of momemtum? A C E
4
B D
A car of mass 800 kg is moving at a velocity of 50 ms-1 The momemtum of the car is A C E
3
Ns kg s-2
2.0 Ns 0.5 Ns 5N
B D
1.5 Ns 3.5 Ns
The figure above shows two objects A and B of masses 3 kg and 2 kg respectively moving towards each other. Which of the following is not true? [ The positive sign if moves to the right and negative sign if moves to the left ] A
The total of momemtum before collision+ 3 kg ms-1 B The total of momemtum after collision+ 3 kg ms-1 C The momentum of object A before collision is + 15 kg ms-1 D The momentum of object B before collision is + 12 kg ms-1 5
TUTORI 27
A man of mass 60 kg runs and suddenly jumps to a trolley of mass 30 kg moves with a velocity of 3 ms -1 in the same direction. After collision the man and the trolley move together with a
9 Figure shows a ticker tape was obtained from an experiment by using trolley A of mass 2kg and trolley B . Trolley A is released from one end of platform so that it moves dowanwards
common velocity of 7 ms-1 . What is the velocity of the man before collision? A C E
6
B D
5 ms-1 9 ms-1
A bullet of mass 10 g is shot horizontally wit a velocity of 200 ms-1 so that it hits an initially stationary block of wood. The bullet enters the block of wood and they move together with a common velocity of 2.0 ms-1 What is the mass of the block of wood. A C E
7
3 ms-1 7 ms-1 12 ms-1
860 g 1000 g 1440 g
B D
and collides with the stationary trolley B. If after collision they stick together,what is the mass of trolley B? A C E
990 g 1020 g
0.5 kg 1.5 kg 2.5 kg
B D
1.0 kg 2.0 kg
10
Two trolleys of masses 2 kg and 3 kg respectively moving towards each other. Both of the trolleys are moving at same velocity of 2 ms-1. . After collision they stick together with a common velocity. What is the common velocity of the trolleys ? A B C D
2 ms-1 in the original direction of the trolley of mass 2kg 2 ms-1 in the original direction of the trolley of mass 3kg 0.4 ms-1 in the opposite direction of the trolley 2 kg 0.4 ms-1 in the opposite direction of the trolley 3 kg
Based on the figure above , what is the value of v ?
8 Figure shows two trolleys of equal mass , m.
C E
v 4 v 4v
B D
2.0 ms-1
B
2.5 ms-1
C
3.0 ms-1
D
3.5 ms-1
E
4.0 ms-1
11 Two objects P and Q of masses 0.8 kg and 0.6 kg respectively moving towards each other. After collision object P bounches back with a velocity of 1.6 ms1 .W What is the velocity and the direction of motion of object Q after collision ?
If after collision they stick together,what is the common velocity of the trolleys? A
A
v 2 2v
A 28
0.8 ms-1 moves to left
B C D
If the recoil velocity of the rifle is 1.25 ms-1,what is the velocity of the bullet ?
0.8 ms-1 moves to right 2.2 ms-1 moves to left 2.2 ms-1 moves to right
12 Two objects M and N of masses 4 kg and 2 kg respectively. Both the objects travel towards each other with velocities of 6 ms-1 and 1 ms-1 respectively. After collision object N moves in the opposite direction as the object with the velocity of 5 ms-1. What is the velocity and the direction of motion of object M after collision ?
A
100 ms-1
B
150 ms-1
C
200 ms-1
D
250 ms-1
E
300 ms-1
15 The total mass of a bullet and a cannon is 300 kg. If the bullet of mass 10 kg is fired from the cannon , the recoil velocity of the cannon is 1.5 ms-1 . Calculate the velocity of the bullet when the bullet is fired.
A 3 ms-1 is the same direction as the object B 3 ms-1 is the opposite direction as the object C 6 ms-1 is same direction as the object D 6 ms-1 is the opposite direction as the object
A C
43.5 ms-1 50.0 ms-1
E
68.5 ms-1
B D
45.0 ms-1 65.0 ms-1
16 A man of mass 50 kg stands on a stationary bot of mass 25 kg. When he jumps out of the boat onto a jetty at a velocity 4 ms-1, calculate the velocity of the boat as the man jumps. A C E
13 Figure shows two identical balls moving towards each other with velocities u and collides with a perfect elastic collision. Which of the following is true after collision? Velocity of P Velocity of Q A Zero Zero B Less than u in Less than u in direction of R direction of S C More than u in More than u in direction of R direction of S D Equals to u in Equals to u in direction of R direction of S
2 ms-1 6 ms-1 10 ms-1
B D
4 ms-1 8ms-1
17 The trolleys A dan B of masses 2 kg and 4 kg respectively are placed together with the plunger of trolley B pressed and in contact with trolley A initially . When the plunger is released by hitting the pin by a hammer ,the two trolleys move apart in opposite directions and collide with the blocks of wood at the same time. What is the value of d ?
14 A bullet of mass 10 g is fired from a rifle of mass 2 kg. 29
A C E
1.0 m 3.0 m 6.0 m
B D
B C D
2.0 m 4.0 m
The elastic collision The explosion The linear motion
23 Which of the following is true? 18 In an inelastic collision , which of the following is not conserved? A B C D
Total Total Total Total
amount amount amount amount
A
The launching of a rocket can be explained by the Newton’s second law of motion B The fuel normally used in rocket engine is liquid hydrogen C The air from atmosfera is sucked into the rocket engine D The total weight of the rocket is constant
of mass of energy of momemtum of mass kinetic energy
19 An object A of mass 4 kg and moving with a velocity of 20 ms-1 collides with a stationary object B with a mass 6 kg . After collision they stick together with a common velocity. What of the following is true ? A B C
24 A rocket and can work in space as well as in atmosphere because A B C
The velocity of object B after collision is 10 ms-1 The total of momemtum after collision is 80 kg ms-1 The total of kinetic energy before collision is equal to the total of kinetic energy after collision
the mass of the rocket is less the velocity of the rocket is high the rocket carries oxygen tank with
it 25 The figure shows a trolley A of mass 1 kg and a stationary trolley B on a frictioncompensated runway.
When they collide , a pin fixed to one trolley sticks into a cork fixed to the other ,keeping them both together. A ticker tape below shows clearly the change of velocity at the moment of collision.
20 The figure above shows two trolleys A and B moving towards each other. Which of the following is true. A An elastic collision will occur B The total momemtum of the system is conserved C The total kinetic energy of the system is conserved D After collision the two trolleys will separate and move with different velocities.
(a)State the type of collision. …………………………………………………… …................
22 Which of the following is not obeys the principle of conservation of momentum ? A
(b) Before collision , wahat is (i) the velocity of the trolley A
The inelastic collision 30
(ii) total of momemtum. (c) Calculate the mass of trolley B. …………………………………………………… …................ (ii) Give one reason for your answer in b(i)
(d) Find the time taken during collision.
……………………………….…………………… …................
(e) Calculate the deceleration of the trolley A during collision? 26
27 The above figure shows a bullet of mass 5 g is released from a pistol and hits a target .
(a) The figure shows two trolleys A and B of masses 1 kg and 2 kg respectively. The velocity of trolley A is 5 ms-1 and trolley B at the rest. After collision trolley A moves with a velocity 2.5 ms-1 in same direction as before.
(a) (i) What happens to the pistol when the bullet is shot out of the pistol. ……………………………………… ….......................
(i) What is the type of the collision which will occur between two trolleys ?
…………………………………………… …................ (ii) Explain the reason for your answer in (a)(i)
…………………………………………… ……...... (ii) What is the velocity of the trolley B after collision. (iii)
…………………………………………… …................
After collision the trolley B moves on a rough surface CD and is stopped in 3.2 s . What is the deceleration of the trolley.
………………………………………… ….................... (b) If the bullet is shot with a velocity 400 ms-1 and hits the target of
mass 0.495 kg and being embedded into it , calculate
(b) If a small marble is placed on the trolley A while the trolley B moves toward trolley B,
(i) The momemtum of the bullet before hits the target.
(i) What will happen to the trolley A when collide with trolley B.?
(ii) The common velocity of the bullet and the target.
…………………………………………………… …................ 31
(iii) The maximum height can that the bullet and the target can reach. 28 Figure below shows a man standing on a stationary boat. He then jumps out of the boat onto the jetty . The boat moves away from the jetty as he jumps.
(a)
(a) State the physics principle that is involved in the movement of the boat as the man jumps onto the jetty.
(b) FIGURE 1
………………………………………………… ……… (b) Explain why the boat moves away from the jetty when the man jumps.
Observe the Figure 1(a) and Figure 1(b). (a) Before the explosion occurs (i) state one similarity between the motions of the objects.
………………………………………………… ………
…………………………………………………
………………………………………………… ……… (c) The mass of the man is 50 kg and he jumps at a velocity of 2 m s-1 . The mass of the boat is 20 kg. Calculate the velocity of the boat as the man jumps.
……….. (ii) the total of momentum of the objects ………………………………………………… ………. (b) After the explosion occurs (i) state one similarity between the motions of the objects. ………………………………………………… ………..
(d) Name one application of the physics principle stated in (a) in an exploration of outer space.
(ii) what is the mathematics sign for the velocity of recoil of the pistol if the bullet which moves to right is considered as having positive sign(+)
………………………………………………… ………… 29 Figure 1(a) shows a bullet of mass 0.01 kg before and after being shot out from a rifle of mass 1.0 kg. Figure 1(b) shows two trolley of masses 0.5 kg before and after its is hit by the hammer
………………………………………………… ……….. (iii) the total of momentum of the objects ………………………………………………… ………. 32
(c) Relate the answers in (a) and (b) to deduce a concept in physics with regard to the explosion of the objects. ………………………………………………… …… ………………………………………………… …… (d) State one application of the pyhsics principle stated in (c) ………………………………………………… ……… (e) What is one physical quantity has the same as the momemtum. ………………………………………………… ……… 30 (a) A car of mass 1 000 kg moving at 20 m s-1 collides with a car of mass 2 000 kg moving at 5 m s-1 in the same direction. If the second car is shunted forwards at 15 m s-1 by the impact, what is the velocity of the first car immediately after the crash?
(b) If the cars collide head-on at the same speed as in (a) , what would their combined velocity , be after the collision if they stick together on impact?
33
The value of momentum Large
The Principle Of Conservation Of Momentum The Principle of conservation of momentum states that “ The total momemtum of a system is always fixed if there is no external force acting on the system” or “ In any collision or interaction between two or more objects in an isolated system , the total momemtum of the system will remain constant ; that is the total momemtum before collision will be equal to the total momemtum after the collision”
Large
Conclusion : Momentum of an object is defined as the product of its .………………. and…………… or momentum = mass x velocity p =mv The S.I . units of momemtum is kgms-1 or Ns
Types of collision There are two types of collision , that is (i) Inelastic collision (ii) Elastic collision
Momentum is a vector quantity. Example 1
Inelastic collision
A bullet of mass 0.01k g moves with a velocity 200 m s-1. What is the momemtum of the bullet?
In inelastic collision , after two objects moving with their respective velocities do collide, they stick together and move with a common velocity.
Solution
Example 2 A trolley of mass 1.5 kg moves with a velocity 4 ms-1 hits a wall and rebounds along the initial direction with a velocity 3 ms-1 .Calculate (i) The initial momentum (ii) The final momentum (iii) The change of momentum
Based on The Principle Of Conservation Of Momentum, The total momemtum = momemtum before collision
Solution
= = 24
The total after collision
Example 3
Example 5 A trolley of mass trolley 2 kg and moving with a velocity 0.6 ms-1 and collides with a stationary trolley with a mass 1kg . After collision the trolley of mass 2kg and moving with a velocity 0.2 ms-1. What is the velocity of the trolley of mass 1 kg after collision?
A trolley of mass 1 kg and moving with a velocity of 6 ms-1 collides with a stationary trolley with a mass 3 kg . After collision they stick together with a common velocity. What is their common velocity? Solution
Solution
Example 4 A trolley of mass trolley M kg and moving with a velocity 4 ms-1 and collides with a trolley of mass 1 kg and moving in opposite direction with a velocity 2 ms-1 . After collision they stick together with a common velocity 2 ms-1. What is the value of M?
Example 6
Solution
Elastic collision
Based on the figure above, what is the (a) value of x (b) direction of motion of the ball with a mass 2 kg after collision
In elastic collision , after two objects moving with their respective velocities do collide, those two objects will separate and move with different velocities.
Solution
Explosion
Based on The Principle Of Conservation Of Momentum, The total momemtum = momemtum before collision
The total after collision
In explosion, two objects are initially at rest and after explosion those two
= 25
objects will separate and move in opposite directions. Based on The Principle Of Conservation Of Momentum, The total momemtum = momemtum before explosion explosion
The total after
with a common velocity Total amount of kinetic energy is not conserved
= =
with different velocities Total amount of kinetic energy is conserved
The Applications of the Principle of Conservation of Momentum in rockets or jet engines .
Example 7 A bullet of mass 0.05 kg is shot out from a gun of mass 1.5 kg. If the recoil velocity of the gun is 2 ms-1,what is the velocity of the bullet ?
Rocket Engine
Solution Example 8 A boy of mass 60 kg and a girl of mass 40 kg stand facing each other on a skating rink. The girl pushes the boy and he moves backwards at 2 ms-1 . What is the girl’s velocity?
Jet Engine
Solution
Similarities and Differences between Inelastic Collision and Elastic Collision
A rocket engine carries its fuel with it and can work in space as well as in atmosphere. Two fuels, such as liquid hydrogen and liquid oxygen burn together explosively and force the gases produced out of the rocket nozzle in high speed and hence produces downwards momemtum. Following the principle of Conservation of Momemtum, the rocket will propel upwards with a momemtum that is equal to its previous momemtum because momemtum is conserved.
Similarities Total momemtum is conserved Total energy is conserved Total mass is conserved Differences Inelastic collision Both objects stick together after collision and move
Elastic collision Both objects don’t stick together after collision and move 26
A jet engine uses the same principle of momemtum conservation as the rocket engine except that it takes in air to burn the fuel.So a jet engine will only work in the atmosfera. In the jet engine, air is sucked into the jet engine to be compressed and is heated up in the compressor. The compressed air is then mixed with fuel which is sprayed so that it starts to burn. The exhaust chamber emits exhaust gases with a high velocity. This results in a momemtum of equal magnitude but of opposite direction which moves the aeroplane forward.
1
Which of the following is the units of momemtum? A C
2
kg ms-2 kg-1s-2
0.625 kg ms-1 16 kg ms-1 D -1 40000 kg ms
B 4 kg ms-1 850 kg ms-1
A ball of mass 0.5 kg hits the wall with a velocity of 4 ms-1 and bounches back with a velocity of 3 ms-1. What is the magnitude of the change of momemtum? A C E
4
B D
A car of mass 800 kg is moving at a velocity of 50 ms-1 The momemtum of the car is A C E
3
Ns kg s-2
2.0 Ns 0.5 Ns 5N
B D
1.5 Ns 3.5 Ns
The figure above shows two objects A and B of masses 3 kg and 2 kg respectively moving towards each other. Which of the following is not true? [ The positive sign if moves to the right and negative sign if moves to the left ] A
The total of momemtum before collision+ 3 kg ms-1 B The total of momemtum after collision+ 3 kg ms-1 C The momentum of object A before collision is + 15 kg ms-1 D The momentum of object B before collision is + 12 kg ms-1 5
TUTORI 27
A man of mass 60 kg runs and suddenly jumps to a trolley of mass 30 kg moves with a velocity of 3 ms -1 in the same direction. After collision the man and the trolley move together with a
9 Figure shows a ticker tape was obtained from an experiment by using trolley A of mass 2kg and trolley B . Trolley A is released from one end of platform so that it moves dowanwards
common velocity of 7 ms-1 . What is the velocity of the man before collision? A C E
6
B D
5 ms-1 9 ms-1
A bullet of mass 10 g is shot horizontally wit a velocity of 200 ms-1 so that it hits an initially stationary block of wood. The bullet enters the block of wood and they move together with a common velocity of 2.0 ms-1 What is the mass of the block of wood. A C E
7
3 ms-1 7 ms-1 12 ms-1
860 g 1000 g 1440 g
B D
and collides with the stationary trolley B. If after collision they stick together,what is the mass of trolley B? A C E
990 g 1020 g
0.5 kg 1.5 kg 2.5 kg
B D
1.0 kg 2.0 kg
10
Two trolleys of masses 2 kg and 3 kg respectively moving towards each other. Both of the trolleys are moving at same velocity of 2 ms-1. . After collision they stick together with a common velocity. What is the common velocity of the trolleys ? A B C D
2 ms-1 in the original direction of the trolley of mass 2kg 2 ms-1 in the original direction of the trolley of mass 3kg 0.4 ms-1 in the opposite direction of the trolley 2 kg 0.4 ms-1 in the opposite direction of the trolley 3 kg
Based on the figure above , what is the value of v ?
8 Figure shows two trolleys of equal mass , m.
C E
v 4 v 4v
B D
2.0 ms-1
B
2.5 ms-1
C
3.0 ms-1
D
3.5 ms-1
E
4.0 ms-1
11 Two objects P and Q of masses 0.8 kg and 0.6 kg respectively moving towards each other. After collision object P bounches back with a velocity of 1.6 ms1 .W What is the velocity and the direction of motion of object Q after collision ?
If after collision they stick together,what is the common velocity of the trolleys? A
A
v 2 2v
A 28
0.8 ms-1 moves to left
B C D
If the recoil velocity of the rifle is 1.25 ms-1,what is the velocity of the bullet ?
0.8 ms-1 moves to right 2.2 ms-1 moves to left 2.2 ms-1 moves to right
12 Two objects M and N of masses 4 kg and 2 kg respectively. Both the objects travel towards each other with velocities of 6 ms-1 and 1 ms-1 respectively. After collision object N moves in the opposite direction as the object with the velocity of 5 ms-1. What is the velocity and the direction of motion of object M after collision ?
A
100 ms-1
B
150 ms-1
C
200 ms-1
D
250 ms-1
E
300 ms-1
15 The total mass of a bullet and a cannon is 300 kg. If the bullet of mass 10 kg is fired from the cannon , the recoil velocity of the cannon is 1.5 ms-1 . Calculate the velocity of the bullet when the bullet is fired.
A 3 ms-1 is the same direction as the object B 3 ms-1 is the opposite direction as the object C 6 ms-1 is same direction as the object D 6 ms-1 is the opposite direction as the object
A C
43.5 ms-1 50.0 ms-1
E
68.5 ms-1
B D
45.0 ms-1 65.0 ms-1
16 A man of mass 50 kg stands on a stationary bot of mass 25 kg. When he jumps out of the boat onto a jetty at a velocity 4 ms-1, calculate the velocity of the boat as the man jumps. A C E
13 Figure shows two identical balls moving towards each other with velocities u and collides with a perfect elastic collision. Which of the following is true after collision? Velocity of P Velocity of Q A Zero Zero B Less than u in Less than u in direction of R direction of S C More than u in More than u in direction of R direction of S D Equals to u in Equals to u in direction of R direction of S
2 ms-1 6 ms-1 10 ms-1
B D
4 ms-1 8ms-1
17 The trolleys A dan B of masses 2 kg and 4 kg respectively are placed together with the plunger of trolley B pressed and in contact with trolley A initially . When the plunger is released by hitting the pin by a hammer ,the two trolleys move apart in opposite directions and collide with the blocks of wood at the same time. What is the value of d ?
14 A bullet of mass 10 g is fired from a rifle of mass 2 kg. 29
A C E
1.0 m 3.0 m 6.0 m
B D
B C D
2.0 m 4.0 m
The elastic collision The explosion The linear motion
23 Which of the following is true? 18 In an inelastic collision , which of the following is not conserved? A B C D
Total Total Total Total
amount amount amount amount
A
The launching of a rocket can be explained by the Newton’s second law of motion B The fuel normally used in rocket engine is liquid hydrogen C The air from atmosfera is sucked into the rocket engine D The total weight of the rocket is constant
of mass of energy of momemtum of mass kinetic energy
19 An object A of mass 4 kg and moving with a velocity of 20 ms-1 collides with a stationary object B with a mass 6 kg . After collision they stick together with a common velocity. What of the following is true ? A B C
24 A rocket and can work in space as well as in atmosphere because A B C
The velocity of object B after collision is 10 ms-1 The total of momemtum after collision is 80 kg ms-1 The total of kinetic energy before collision is equal to the total of kinetic energy after collision
the mass of the rocket is less the velocity of the rocket is high the rocket carries oxygen tank with
it 25 The figure shows a trolley A of mass 1 kg and a stationary trolley B on a frictioncompensated runway.
When they collide , a pin fixed to one trolley sticks into a cork fixed to the other ,keeping them both together. A ticker tape below shows clearly the change of velocity at the moment of collision.
20 The figure above shows two trolleys A and B moving towards each other. Which of the following is true. A An elastic collision will occur B The total momemtum of the system is conserved C The total kinetic energy of the system is conserved D After collision the two trolleys will separate and move with different velocities.
(a)State the type of collision. …………………………………………………… …................
22 Which of the following is not obeys the principle of conservation of momentum ? A
(b) Before collision , wahat is (i) the velocity of the trolley A
The inelastic collision 30
(ii) total of momemtum. (c) Calculate the mass of trolley B. …………………………………………………… …................ (ii) Give one reason for your answer in b(i)
(d) Find the time taken during collision.
……………………………….…………………… …................
(e) Calculate the deceleration of the trolley A during collision? 26
27 The above figure shows a bullet of mass 5 g is released from a pistol and hits a target .
(a) The figure shows two trolleys A and B of masses 1 kg and 2 kg respectively. The velocity of trolley A is 5 ms-1 and trolley B at the rest. After collision trolley A moves with a velocity 2.5 ms-1 in same direction as before.
(a) (i) What happens to the pistol when the bullet is shot out of the pistol. ……………………………………… ….......................
(i) What is the type of the collision which will occur between two trolleys ?
…………………………………………… …................ (ii) Explain the reason for your answer in (a)(i)
…………………………………………… ……...... (ii) What is the velocity of the trolley B after collision. (iii)
…………………………………………… …................
After collision the trolley B moves on a rough surface CD and is stopped in 3.2 s . What is the deceleration of the trolley.
………………………………………… ….................... (b) If the bullet is shot with a velocity 400 ms-1 and hits the target of
mass 0.495 kg and being embedded into it , calculate
(b) If a small marble is placed on the trolley A while the trolley B moves toward trolley B,
(i) The momemtum of the bullet before hits the target.
(i) What will happen to the trolley A when collide with trolley B.?
(ii) The common velocity of the bullet and the target.
…………………………………………………… …................ 31
(iii) The maximum height can that the bullet and the target can reach. 28 Figure below shows a man standing on a stationary boat. He then jumps out of the boat onto the jetty . The boat moves away from the jetty as he jumps.
(a)
(a) State the physics principle that is involved in the movement of the boat as the man jumps onto the jetty.
(b) FIGURE 1
………………………………………………… ……… (b) Explain why the boat moves away from the jetty when the man jumps.
Observe the Figure 1(a) and Figure 1(b). (a) Before the explosion occurs (i) state one similarity between the motions of the objects.
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………………………………………………… ……… (c) The mass of the man is 50 kg and he jumps at a velocity of 2 m s-1 . The mass of the boat is 20 kg. Calculate the velocity of the boat as the man jumps.
……….. (ii) the total of momentum of the objects ………………………………………………… ………. (b) After the explosion occurs (i) state one similarity between the motions of the objects. ………………………………………………… ………..
(d) Name one application of the physics principle stated in (a) in an exploration of outer space.
(ii) what is the mathematics sign for the velocity of recoil of the pistol if the bullet which moves to right is considered as having positive sign(+)
………………………………………………… ………… 29 Figure 1(a) shows a bullet of mass 0.01 kg before and after being shot out from a rifle of mass 1.0 kg. Figure 1(b) shows two trolley of masses 0.5 kg before and after its is hit by the hammer
………………………………………………… ……….. (iii) the total of momentum of the objects ………………………………………………… ………. 32
(c) Relate the answers in (a) and (b) to deduce a concept in physics with regard to the explosion of the objects. ………………………………………………… …… ………………………………………………… …… (d) State one application of the pyhsics principle stated in (c) ………………………………………………… ……… (e) What is one physical quantity has the same as the momemtum. ………………………………………………… ……… 30 (a) A car of mass 1 000 kg moving at 20 m s-1 collides with a car of mass 2 000 kg moving at 5 m s-1 in the same direction. If the second car is shunted forwards at 15 m s-1 by the impact, what is the velocity of the first car immediately after the crash?
(b) If the cars collide head-on at the same speed as in (a) , what would their combined velocity , be after the collision if they stick together on impact?
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