A crane is being used to lift containers off a ship. One container has a mass of 14 000 kg and is being lifted vertically with a speed of 3.2 m s⁻¹. The electric motor being used to supply the power to lift the container is using a current of 240 A at a potential difference of 2200 V. What is the efficiency of the system?

The data below are taken from a test of a petrol engine for a motor car. power output = 150 kW fuel consumption = 20 …

A ball is thrown vertically upwards from the surface of the Earth. Which statement describes the energy of the ball a…

A sledge of mass 50 kg sits on a snowy surface. It is pulled horizontally for 10 m against a frictional force of 200 …

Diffraction is a term used to describe one aspect of wave behaviour. What does diffraction make possible?

Monochromatic light of wavelength 5.30 × 10⁻⁷ m is incident normally on a diffraction grating. The first order maximu…

The electric field strength at a certain distance from an isolated alpha particle is 3.0 × 10⁷ N C⁻¹. What is the for…