Movement in a circle and centripetal force
Galileo - Everybody continues to move with a constant speed unless acted on by a resultant force.
From this Newton established his first law of motion.
An object that is moving in a circle is said to be accelerating, even if there is no speed change, because the velocity is constantly changing.
In GCSE physics curriculum, a net inward force is needed to provide this acceleration. This 'centripetal' force, f, always acts towards the centre of the circle and is given by:
F=ma
As an object is travelling at a constant speed in a circle, the centripetal force acts at right angles to the direction in which the object is travelling in at any instant.
In GCSE physics, the amount of centripetal force need to keep an object moving in a circle depends on:
- the mass of the object: the larger the mass, the larger the force needed
- the speed of the object: the faster the speed, the larger the force needed
- the radius of the circle: the smaller the radius, the larger the force needed
The mass is constantly accelerating towards the center, O, with a magnitude (m/s2) given by:
a = v2/r
Please be reminded that in GCSE physics curriculum, the speed of the object travelling equates to diameter/time.
End of this topic!
Drafted by Gina (Physics)