Ap Physic Momen-2

Objective: -

To understand the concept of momentum To demonstrate the Law of Conservation of Momentum To apply the concept of momentum into the experiment To illustrate momentum theory in real life To compare the result between elastic and inelastic momentum

Introduction: The momentum is the measurement of mass in motion. In addition, the momentum of an object is defined as the product of its mass and the velocity at which it is moving according to this equation, P = mv . P is the symbol that used for the momentum, M is mass, and V is the velocity. The momentum is the vector quality, and the standard units for the momentum is k g × m/s 2 . This create the simple relationship between mass, velocity and momentum. If either the mass or velocity of an object is double, the momentum of the object will also be double. Momentum can also be thought of as the inertia in motion because the more momentum a moving object has, the harder to stop it moving. Furthermore, two different mass of the object can have the same momentum depending on their respective velocity. The conservation of momentum is means that there is no unbalanced forces acting on a system, the total momentum of the system is remain constant. The two main types of the conservation of momentum are the inelastic collision, and elastic collision. The inelastic collision is happen when two objects stick together after the collision. The momentum is conserved, but the kinetic energy are not conserved. The loss of the kinetic energy have been transfer to something else such as the thermal energy, and sound energy. On the other hand, the elastic collision is happen when the colliding objects bounce off each other. Both the momentum and the kinetic energy are conserved.

In the experiment, we use two cart running on the dynamics track to create the inelastic and elastic collision. First, we put the cart the side that have the velcro tape face together. Then, we putting one cart to make in collided with the other resting cart on the other side of the dynamics track and stick together to create the inelastic collision. Second, we put the cart that have the magnetic face together. Then, we putting one of the cart to make in collided with the other resting cart on the other side of the dynamics track and bounce off each other to create the elastic collision.

Material: 1. 2. 3. 4. 5. 6. 7.

Cart track Experimenting cart Two indicators Track holder Soft sponge Timer Data table

Procedure: 1. Set up the track for the cart and lift one end of the track with an inclined angle. Used the track holder to hold the higher end of the track. 2. Put a soft sponge at the other end of the track to let it acts as a cart stopper. 3. Install two indicators on the track; one at the 80cm point, another one at the 140cm point. 4. Start your trial by putting your cart on the higher end of the track. Make sure you indicated your starting point at 20cm point. 5. Release the cart from the starting point. Start your timer as you release the cart. 6. Stop the timer as the cart passed the 80cm point and 140cm point respectively. Record your time on the data table.

Set up:

Data table: Ineastic collision Mass (kg)

Intinal Velocity

Final Veolcity

Cart 1

0.514

0.10

-0.25

Cart 2

0.514

-0.8

-0.25

I determine the initial velocity and final velocity by estimate from the graph that show the result from the experiment. The red and blue line is cart 1. The green and purple line is cart 2.

Eastic collision Mass (kg)

Intinal Velocity

Final Veolcity

Cart 1

0.514

0.57

0

Cart 2

0.514

0

0.48

I determine the initial velocity and final velocity by estimate from the graph that show the result from the experiment. The red and blue line is cart 1. The green and purple line is cart 2.

Calculation: Inelastic collision m1= 0.514 kg m2 = 0.514 kg u1 = 0.10 m/s u2 = -0.8 m/s v1 = -0.25 m/s v2 = -0.25 m/s P i=P

f

m 1u 1 + m 2u 2 = m 1v 1 + m 2v 2 (0.514)(0.10) + (0.514)(-0.8) = (0.514)(-0.25) + (0.514)(-0.25) -0.3598 k g · m/s = -0.257 k g · m/s % different = −0.3598−0.257 × 100 −0.3598 % different = 28.57% Elastic collision m1= 0.514 kg m2 = 0.514 kg u1 = 0.57 m/s u2 = 0 m/s v1 = 0 m/s v2 = 0.48 m/s P i=P

f

m 1u 1 + m 2u 2 = m 1v 1 + m 2v 2 (0.514)(0.57) + (0.514)(0) = (0.514)(0) + (0.514)(0.48)   0.293 kg · m/s = 0.247 kg · m/s     % dif f erent =

0.293−0.247 0.293

% dif f erent = 15.69%  

× 100  

Analysis: The experiment result of the elastic collision confirmed the theory that the momentum before and after the collision is nearly the same value. The value of difference is come from friction between the track and the cart. The percent difference between the momentum before and after the collision is about 15.69% This confirmed that both momentum and kinetic energy is conserved. The result from the inelastic collision have nearly the same value between before and after the collision because the momentum is conserve. But, the the kinetic energy have been loss and transfer to something else such as the thermal energy, and sound energy because the cart have stick together with the same velocity after the collision. The percent difference is about 28.57% due to the friction between the cart and the railway. This show that the momentum is conserved.

Conclusion: In conclusion, this experiment show that both momentum and kinetic energy is conserved in elastic collision. But, only the momentum is conserved in inelastic collision. The kinetic energy is not conserved.

Recommendation: I recommended that the student who do this experiment should pushed the cart in elastic collision at the same force. This will reduce the percent error of the experiment and make the result become more precise.

Reference: -

(n.d.). Retrieved from http://aplusphysics.com/courses/honors/momentum/collisions.html

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Momentum and Collisions. (n.d.). Retrieved from https://www.physicsclassroom.com/calcpad/momentum

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Momentum - Elastic and Inelastic Collision. (n.d.). Retrieved from http://acartoonguidetophysics.blogspot.com/2011/10/momentum-elastic-and-inelastic. html