Dynamics

What is the unit of acceleration?

• ms^-2

• ms

• km^s

• kms^-2

The net force required to accelerate a 150.0 kg car at 10.00 m/s² is

• 150 N

• 1500 N

• 1.500 x 10² N

• 1.5 x 10³ N

If you took the area under the line of the graph above, which quantity would you calculate?

• Force

• Speed

• Work

• Acceleration

Which of the following units are equivalent to a Joule?

• kg x m/s²

• N x m

• kg x m²/s²

• both b and c

• none of these answers

Two astronauts are launched into space in the same space capsule. One astronaut has a much greater mass than the other astronaut. After completing just one orbit, the astronauts make an emergency return to Earth. How does the kinetic energy of the more massive astronaut in orbit compare to the kinetic energy of the less massive astronaut in orbit?

• The kinetic energy is the same for both astronauts

• The kinetic energy is greater for the less massive astronaut

• The kinetic energy is greater for the more massive astronaut

• The kinetic energy cannot be determined from the given information.

Each diagram illustrates a pair of forces of equal magnitude.Which diagram gives an example of a pair of forces that is described by Newton’s third law of motion?

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A helium atom of mass m collides normally with a wall. The atom arrives at the wall with speed v and then rebounds along its original path. Assume that the collision is perfectly elastic.

What is the change in the momentum of the atom during its collision?

• zero

• 0.5 mv

• mv

• 2 mv

Two objects X and Y in an isolated system undergo a perfectly elastic collision. The velocities of the objects before and after the collision are shown.

What is the speed v of Y after the collision?

• 2.0 m s^–1

• 18 m s^–1

• 22 m s^–1

• 24 m s^–1

The mass of a rocket-propelled truck is approximately equal to the mass of the fuel in its tank.

The fuel is ignited and the truck is propelled along horizontal tracks by a constant force. The effect of air resistance is negligible.

During a test run the fuel is consumed at a constant rate.

Which statement describes the acceleration of the truck during the test run?

• The acceleration of the truck decreases as the fuel is consumed.

• The acceleration of the truck increases as the fuel is consumed.

• The acceleration of the truck remains constant.

• The acceleration of the truck is zero and the truck moves at a constant velocity.

1N is the force required to

• accelerate 1g to 1m/s in 1s

• accelerate 1kg to 1m/s in 1s

• accelerate 1kg to 1m/s in 1min