EVERYDAY SCIENCE

Detailed explanation-1: -Gravity is a force of attraction between masses. It provides the centripetal force needed to keep a satellite in orbit around a planet, or a planet in orbit around a star such as the Sun. The motion of the moon around the earth is due to the centripetal force.

Detailed explanation-2: -The Short Answer: Gravity-combined with the satellite’s momentum from its launch into space-cause the satellite to go into orbit above Earth, instead of falling back down to the ground.

Detailed explanation-3: -When a satellite moves around the Earth, then the direction of force of gravity on the satellite is perpendicular to its displacement. Hence, the work done on the satellite by the Earth is zero.

Detailed explanation-4: -The only force on a satellite is the force of gravity. A satellite remains in orbit because this force of gravity provides the centripetal force necessary for it to move in a circle.

Detailed explanation-5: -A satellite in a perfectly circular orbit is moving tangentially to the earth’s surface-parallel to the ground. Gravity is pulling straight downwards, perpendicular to that orbital path. So gravity does no work.