Which quantity has the same units as those for energy stored per unit volume?

• Density

• Force

• momentum

• Pressure

An object of mass m strikes a vertical wall horizontally at speed U. The object rebounds from the wall horizontally at speed V.

What is the magnitude of the change in the momentum of the object?

• 0

• m(V-U)

• m(U-V)

• m(U+V)

An ideal gas of constant mass is heated in a container of constant volume.

What is the reason for the increase in pressure of the gas?

• The average number of molecules per unit volume increases.

• The average force per impact at the container wall increases.

• Molecules collide with each other more frequently.

• Molecules occupy a greater fractional volume of the container.

A substance in the gas state has a density about 1000 times less than when it is in the liquid state. The diameter of a molecule is d. What is the best estimate of the average distance between molecules in the gas state?

• d

• 10d

• 100d

• 1000d

A current in a wire lies between the poles of a magnet. What is the direction of the electromagnetic force on the wire?

• A

• B

• C

• D

Four resistors of 4 Ω each are connected as shown.

What is the effective resistance between P and Q?

• 1.0 Ω

• 2.4 Ω

• 3.4 Ω

• 4.0 Ω

Which quantity has the fundamental SI units of kg m –1s–2?

• Energy

• Force

• Momentum

• Pressure

Two forces act along a straight line on an object that is initially at rest. One force is constant; the second force is in the opposite direction and proportional to the velocity of the object.

What is correct about the motion of the object?

• The acceleration increases from zero to a maximum.

• The acceleration increases from zero to a maximum and then decreases.

• The velocity increases from zero to a maximum.

• The velocity increases from zero to a maximum and then decreases.

A climber of mass m slides down a vertical rope with an average acceleration a. What is the average frictional force exerted by the rope on the climber?

• mg

• m (g + a)

• m (g - a)

• ma

A transverse travelling wave is moving through a medium. The graph shows, for one instant, the variation with distance of the displacement of particles in the medium.

The frequency of the wave is 25 Hz and the speed of the wave is 100 m s–1 . What is correct for this wave?

• The particles at X and Y are in phase.

• The velocity of the particle at X is a maximum.

• The horizontal distance between X and Z is 3.0 m.

• The velocity of the particle at Y is 100 m s–1.