Test Physics (force And Pressure + Heat)

Section A Answer all questions F A B iD g u r e

5m 1 3

C

1. Figure 1 shows four shoe heels of different shapes worn by the same lady. Which shoe heel exerts the greatest pressure on the ground?

2. Figure 2 shows a tank which is 5 m long, 1 m, deep and 3 m wide and is filled with water of weight 20 N.

Figure 2 What is the pressure on the base of the tank due to the water? A. 1.3 Pa B. 2.6 Pa C. 4.0 Pa D. 20.0 Pa

3. Pressure is defined as the force… A. Acting normally at a point B. Acting normally per unit mass C. Acting normally per unit area D. Acting normally in all directions at a point

4. A barometer is carried from the first floor to the 50th floor of Sipitang Twin Tower. Why does the reading on the barometer fall? A. Gravitational attraction has decreased. B. Air temperature has increased. C. Air pressure has increased. D. The air above the barometer becomes less dense.

5. Water flow out from a hole at the side of container which is fully filled with F Water iflow g u r e

water as shown in figure 3.

What will happen to the rate of flow of water if the container is closed tightly with a lid? A. Water flows out faster B. Water flows out slower C. Water stop flowing D. Water will get hot 6. A wooden block is found to sink in a liquid P and float on the surface of another liquid Q. Which of the following statements gives the correct comparison between the density of the two liquids and the wooden block? A. Liquid P is denser than the wooden block B. Liquid P is less dense than liquid Q C. Liquid Q is less dense than the wooden block D. Liquid P is denser than liquid Q

7. Figure 4 shows a person sucking a drink through a drinking straw.

Figure 4 The drink enters the mouth because… A. The straw acts as a capillary tube B. It is sucked up by the vacuum in the lungs C. It is pushed up by the atmospheric pressure D. It is drawn up by the pull of the air in the straw

8. A manometer is connected to a gas supply as shown in figure 5.

Figure 5 The pressure of the gas is… A. 6 cm of water more than the atmospheric pressure. B. 8 cm of water more than the atmospheric pressure.

C. 6 cm of water less than the atmospheric pressure. D. 2 cm of water more than the atmospheric pressure.

9. Figure 6 shows a hydraulic pump. The ratio of the area of cross-section of position P to that position of Q is 1: 10 and the force acting on piston P is 20 N.

Load

Q

P

Figure 6 Which of the following statement is correct? A. The weight of the load which can be lifted is 20 N. B. The weight of the load which can be lifted is 200 N. C. The pressure exerted on piston P is 10 times longer than that exerted on piston Q. D. The pressure exerted on piston P is 10 times smaller than that exerted on piston Q. 10.A box made of metal is submerged underwater. A diver who is trying to lift the box to the surface finds that it is much easier to lift it underwater compared to on the surface. This is due to … A. Upward force B. Buoyant force C. Weightlessness D. Surface tension

F i g u r e

11.Figure 7 shows a log of 5 kg floating freely on the sea water.

What is the buoyant force acting on the log? A. 5 N B. 10 N C. 50 N D. 100 N

12.Which of the following does not apply Archemedes’ principle? A. Submarine B. Hydrometer C. Hot-air balloon D. Bunsen burner

13.Figure 8 shows a ping-pong ball that does not fall under the water flow.

Figure 8 Which principle can be used to explain this phenomenon? A. Archemedes’ principle B. Pascal’s principle C. Torricelli’s principle D. Bernoulli’s principle

14.An object shaped like an aerofoil is moving horizontally with accelerated speed in the direction shown by the arrow in figure 9.

R

S

T

Figure 9 Which of the following statements is incorrect? A. The speed of air flow is higher in the region R than in S B. The air pressure is higher in region S than in R C. The lift on the object equal to the weight of the object D. The resultant force in the

15.Which are the correct SI unit of heat and temperature? A

Heat Degree

Temperature Joule

B C

Celsius Joule Degree

Kelvin Kelvin

D

Celsius Joule

Degree Celsius

16.Thermal equilibrium occurs when… A. The net transfer of heat between two objects in thermal contact is maximum. B. The net transfer of heat between two objects in thermal contact is minimum. C. The net transfer of heat between two objects in thermal contact is zero. D. No heat is transferred between two objects.

17.In order to make the mercury thermometer measure small changes in temperature accurately, you would… A. Put the degree marking closer together. B. Decrease the diameter of the capillary tube. C. Put the degree marking further apart. D. Decrease the volume of the mercury bulb

18.A length of mercury in an uncelebrated thermometer is 4 cm when the thermometer is placed in pure melting ice and 44 cm when it is placed in pure steam. When placed in a liquid X, the length is 48 cm. What is the temperature of the liquid X? A. 48 °C B. 109 °C C. 110 °C D. 140 °C

19.A block of iron of mass 2 kg at temperature 30 °C is heated with an electrical heater rated 100 W for 2 minutes. What is the final temperature of the block of iron? [Specific heat capacity of an iron = 452 J kg-1 °C-1 A. 16.7 °C B. 30.0 °C C. 30.2 °C D. 43.3 °C

20.Which of the following reason for using water as a coolant in the radiator of a car engine? A. Water is colorless. B. Water is a good solvent. C. Water is a conductor of electricity. D. Water has a high specific heat capacity.

Section B 1. Figure 10(a) shows a small aeroplane and figure 10(b) shows a much larger aeroplane.

Figure 10 (a)

Figure 10 (b) a) i.

Explain how an aeroplane obtains a lift force in terms of pressure difference?

ii. Observe figure 10 (a) and figure 10 (b) and compare the wing size and the weights of the two planes. Relating the weights of planes to lift required during flight, deduce a relevant physics concept relating size of the wings and the lift force experienced by the wing. iii. What is the physics principle involved in (a)? b) Figure 11 shows a hydrofoil boat.

The hydrofoil results in a lift force on the aerofoil of an aeroplane. The surface area of the hydrofoil is much smaller than the surface area of the aerofoil. Explain how the hydrofoil is able to produce enough lift with the smaller surface area.

2. Figure 12 shows a copper rod being heated in boiling water for several minutes and the hot copper rod transferred into a beaker of water.

Figure 12 The temperature of the water in the beaker is measured at 15 second intervals starting from the moment the copper rod is transferred into the water. The water is constantly stirred slowly with the glass rod stirrer. a. Explain why it is necessary to stir the water constantly. The graph showed in figure 13 shows the variation of temperature of the water with time.

b. At the moment the copper rod was transferred into the water, i.

What was the temperature of the copper block?

ii. What was the temperature of the water? c. Why does the temperature of water rise? d. What was the temperature of copper rod when the temperature of the water becomes constant? Specific heat capacity of copper = 390 J kg C Specific heat capacity of water = 4200 J kg C e. Calculate the amount of heat lost by the copper block if its mass is 0.50 kg. f. i.

What was the amount of heat gain by the water?

ii. Explain your answer on (f) (i). g. Calculate the mass of the water.