A centripetal force is any force that makes an object follow a circular path. In fact, the meaning of the word centripetal is " center seeking " or " toward the center "
There are many real life examples of this force. Take a look at the following examples.
Imagine using a string to spin the green ball you see above. According to Newton's first law of motion, the ball should have stayed in a straight path. However, this is not the case. The ball follows instead a circular path because the string is pulling the ball back toward the center or toward the black dot. Without this force, the ball will not revolve. Instead, it would just move along a straight line.
A gravitational force is directed toward the center of the earth. This force is also a centripetal force keeping the moon in almost circular orbit around the earth.
Car driving around a curve
When a car drives around a curve, there must be sufficient frictional force in place between the tires and the road to provide the required centripetal force. Otherwise, the car will skid instead of going around the curve.
To find this force, you can use Newton's second law of motion.F = m × a
m is the mass of the object
a is the centripetal acceleration given by the following formula. We will prove the formula for centripetal acceleration in another lesson.
A car with a weight of 1000 kg is going around a circular path that has a radius of 400 meters with a speed of 20 m/s. What is the centripetal force exerted on the car?
F = mv2 / r
F = [1000(20)2] / 400
F = [1000(400)] / 400
F = 400000 / 400
F = 1000
The centripetal force exerted on the car is 1000 Newtons.