Kinematics and Dynamics

A student cycles uphill from home to a shop, taking 10 minutes. The student then spends 5 minutes in the shop, before cycling home downhill at twice the initial speed.

Which graph could show the variation with time of the distance travelled by the cyclist?

• A

• B

• C

• D

Two cars X and Y are travelling along the same straight road. Car X is travelling at a constant speed of 6.0 m s^–1. Car Y has a constant acceleration of 0.50 m s^–2.

At the instant shown, car X is a distance d ahead of car Y. Car Y is travelling at a speed of 4.0 m s^–1.

Car Y is level with car X after a time of 20 seconds.

What is the distance d ?

• 40 m

• 60 m

• 180 m

• 300 m

The graph shows how quantity P varies with quantity Q for an object falling in air for a long time in a uniform gravitational field.

What could be the identities of P and Q?

• P: force of air resistance, Q: acceleration

• P: kinetic energy, Q: time

• P: gravitational potential energy, Q: height

• P: work done against air resistance, Q: speed

A stone is thrown vertically upwards from a point X at time

t ꞊ 0.

The variation with time t of the velocity v of the stone is shown.

What is the displacement of the stone from point X at time

t ꞊ 3.0 s?

• 15 m above X

• 15 m below X

• 25 m above X

• 25 m below X

A mass of 5.0 kg is released from rest on a frictionless surface inclined at 30^o to the horizontal. Air resistance is negligible.

How far does the mass travel in a time of 0.80 s?

• 1.6 m

• 2.0 m

• 2.7 m

• 3.1 m

What is not a statement of one of Newton’s laws of motion?

• If body X exerts a force on body Y, body Y exerts an equal and opposite force on body X.

• If no resultant force acts on a body it has constant velocity.

• The rate of change of momentum of a body is proportional to the resultant force acting on it and takes place in the direction of the force.

• The total momentum of a system of interacting bodies is constant if there is no external force.

In a high-wire circus act, a man of mass 85 kg is standing at rest at the midpoint of the wire.

The wire on either side of the man is at an angle of 20^o to the horizontal. What is the tension T in the wire?

• 0.44 kN

• 0.89 kN

• 1.2 kN

• 2.4 kN