The universal law of gravitation was proposed by:

According to Kepler's third law, the square of the orbital period of a planet is proportional to:

The value of the universal gravitational constant G is approximately:

A collision in which kinetic energy is not conserved is called:

Weight of a body is the force of gravity acting on its:

Which of the following best describes 'inertia'?

An astronaut in orbit experiences apparent weightlessness because:

The escape velocity from Earth's surface is approximately:

Gravitational potential energy between two masses is always:

A ball rolling on a frictionless horizontal surface will:

The gravitational force between two objects increases when: