Circular motion

Question 1

Why does an object move in a circular motion?

Answer 1

For circular motion to occur there must be a force acting inwards along the radius of the circle. This is called the centripetal force. The object moves at right angles to this force.

Question 2

How does circular motion act on a satellite?

Answer 2

If there were no forces acting on the satellite it would move in a straight line. The gravitational force, acting towards the earth acts on the moving satellite. This is the centripetal force and it acts at ninety degrees to the direction of motion of the satellite. The speed of the satellite remains constant, but the velocity constantly changes due to the change in direction. This means that the satellite is accelerating even though it is traveling at a constant speed.

Question 3

What are the four main types of centripetal force that will result in circular motion?

Answer 3

Gravitational - orbiting satellite.
Frictional - car on a roundabout.
Tension - a hammer thrower.
Electrostatic - electron orbiting nucleus.