17.2 Space practice A Level Physics

A helicopter circles continuously at a constant speed around a horizontal path of diameter 800 m, taking 5.0 minutes to complete each orbit of the path.

What are the speed v and the centripetal acceleration a of the helicopter?

• A

• B

• C

• D

What is the angular speed of a car wheel of diameter 0.400 m when the speed of the car is 108 km h⁻¹?

• 75 rad s⁻¹

• 150 rad s⁻¹

• 270 rad s⁻¹

• 540 rad s⁻¹

A roller coaster car is raised to a height of 65 m and released from rest.

What is the maximum possible speed of the car?

• 11 m s⁻¹

• 25 m s⁻¹

• 36 m s⁻¹

• 130 m s⁻¹

The units of physical quantities can be expressed in terms of the fundamental (base) units of the SI system. In which line in the table are the fundamental units correctly matched to the physical quantity?

• A

• B

• C

• D

Two bodies of different masses undergo an elastic collision in the absence of any external force.

Which row gives the effect on the total kinetic energy of the masses and the magnitudes of the forces exerted on the masses during the collision?

• A

• B

• C

• D

Answer explanation

Elastic means no energy is lost and the forces must be equal and opposite due to 3rd Law

An experiment is carried out to determine the Young modulus E of steel using a vertical wire of initial length L and cross-sectional area A. Various weights are suspended from the wire. A graph of extension against weight is plotted.

What does the gradient of the graph represent?

Two cars P and Q leave from the same point and travel in the same direction.

Q leaves at time t = 0 and P leaves one second later.

The figure shows the velocity–time graph for P and Q.

What is the distance between Q and P when t = 8 s?

• 40 m

• 80 m

• 160 m

• 180 m

Answer explanation

Area under Q - Area under P