Section A [ 15 marks ]Answer all question in this section.1. A vector quantity has the units of N m. What is this quantity?A. Moment of a forceB. Angular momentumC. Linear momentumD. Work done

2. The acceleration of an object, which is initially at rest, varies with time as shown in the graph below.

Which of the following graphs shows the variation of velocity with time for this object?

3. A rubber ball is dropped from a certain height on a hard floor. It bounces on the ground to a lower height. Which of the following graphs shows the variation of velocity with time for this motion?

4. The graph below shows the variation of velocity with time for a motorcycle.

The power of the motorcycle for increasing its kinetic energy at t = 8 s is 10 kW. What is the mass of the motorcycle and the rider?A. B. 25 kgC. 125 kgD. 200 kgE. 400 kg

5. An object of mass m moving with a velocity u makes a perfectly inelastic collision with a stationary object of mass 2m. Calculate the amount of kinetic energy lost during this collision.A. B. C. D.

6. A stone attached to the end of a string is swung in a vertical circle at constant speed as shown in the diagram below.The tension in the string changes as the stone moves around. When it is at P, the tension is Tp and when it is at Q the tension is TQ. What is the tension when the stone is at R?A. TP + TQ B. TP - TQC. (TP + TQ)D. (TP - TQ)7. At a certain point on a straight line joining the earth and the moon, the force on a mass placed there is zero. The gravitational potential at this point isA. zeroB. maximumC. minimumD. infinity8. If a deep hole is dug in the ground and the acceleration due to free fall, g', is measured at the bottom of the hole, how will it compare with the value of g at the surface?[Take the distance from the centre of the earth to the bottom of the hole to be r and the effective mass of the earth contributing to the acceleration due to free fall to be m.]

9. Which of the following statements is not true of an amorphous solid?A. Glass is an example of an amorphous solid.B. Amorphous solids are actually very highly viscous liquids.C. Molecules in an amorphous solid are arranged in long-range regular lattices.D. Amorphous solids are usually very brittle.

10. The graph shows the variation of potential energy U with separation r for two atoms.

As r increases from ro, the gradient of the graph increases until r = ri. Beyond that, the gradient decreases. At the point where r = ri,A. the resultant force between the atoms is zero.B. the resultant force between the atoms is repulsive and maximum.C. the resultant force between the atoms is attractive and maximum.D. the atoms will remain in equilibrium.

11. Which of the following statements is true for both ideal gases and real gases?A. There are no forces between the molecules except when they collide.B. Volume of the molecules is negligible compared to the volume of the gas.C. Time of collision is negligible compared to the time between two collisions.D. Collision between atoms is perfectly elastic.

12. The p-V graph shows two isothermal changes of the same sample of an ideal gas. Calculate the value of p2

A. B. 0.14 x 105 PaC. 0.16 x 105 PaD. 1.1 x 105 PaE. 1.5 x 105 Pa

13. The equation shown represents the first law of thermodynamics. Which of the following statements are true?

A. U is positive if the temperature of the gas increases.B. Q is negative if heat is absorbed by the gas.C. W is the work done on the gas.D. Q will be more than W in an isothermal compression.

14. The pressure of a diatomic gas increased from P to P during an adiabatic compression. What will the new volume be if the original volume is V?A. B. C. D. E.

15. A composite rod is made of a rod P of length l and thermal conductivity kP and another rod Q also of length l but with thermal conductivity kQ as shown in the diagram.

Both P and Q have the same cross-sectional area. The temperatures at the two ends are maintained at 60C and 20C respectively. The junction temperature is 50C when steady state is reached. Which of the following statements is not true?A. kp>kQ.B. Rate of heat flow in both rods is the same.C. Temperature gradient in P < temperature gradient in Q.D. P has a higher thermal resistance than Q.