Motion, forces and energy - circular motion

newtons first law of motion

a body remains at rest or uniform motion in a straight line unless acted upon an external force

NOTE:

uniform motion = constant speed or velocity
unbalanced force = resultant or net force

centripetal force

is the resultant force acting towards the centre of acicular path to keep it moving in a circle

QUESTIONS

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1. A car travels around a circular track at a constant speed.
(a) why is it incorrect to describe the circular motion as having a constant velocity

This is because according to newtons first law, constant velocity means the body is moving in a straight line

(b) A force is required to maintain the circular motion.
(i) explain why a force is required

An external, unbalanced force is required to keep the body moving in a circle. The body must be accelerating to be able to to move in a circular path.

(ii) In which direction does this force act

towards the centre of the circle path

(iii) suggest what provides this force

the friction force between the tyres and the road