The centripetal force that causes a car to go round a bend in the road is provided by A. the force produced by the car engine acting on the

wheels. B. the friction between the tyres and the road. C. the weight of the car. D. the force exerted by the driver on the steering wheel.

The radius of a loop is measured to be (10.0 ± 0.5) cm. Which of the following is the best estimate of the uncertainty in the calculated area of the loop? A. 0.25% B. 5% C. 10% D. 25%

In Newton’s universal law of gravitation the masses are assumed to be A. extended masses. B. masses of planets. C. point masses. D. spherical masses.

Define gravitational field strength.

the force exerted per unit mass; on a point (small) mass;

The mass of Mars is approximately 0.1 times the mass of Earth and its diameter is approximately 0.5 times that of Earth. What is the approximate gravitational field strength on the surface of Mars? A. 2N kg–1 B. 4N kg–1 C. 25N kg–1 D. 50N kg–1

The gravitational potential at a point P above the surface of a planet is defined as the work done per unit mass in moving a small test mass A. from point P to the surface of the planet. B. from the surface of the planet to point P. C. from point P to infinity. D. from infinity to point P.

A spacecraft orbits Earth. An astronaut inside the spacecraft feels “weightless” because A. the gravitational field in the spacecraft is negligible. B. the Earth exerts equal forces on the spacecraft and the astronaut. C. the spacecraft and the astronaut have the same acceleration towards the Earth. D. the spacecraft and the astronaut exert equal and opposite forces on each other.

The acceleration of free fall of a small sphere of mass 5.0 × 10–3 kg when close to the surface of Jupiter is 25 ms–2. The gravitational field strength at the surface of Jupiter is

A. 2.0 × 10–4 N kg–1.

B. 1.3 × 10–1 N kg–1.

C. 25 N kg–1.

D. 5.0 × 103 N kg–1.