A model train, with a mass of 4 kg, is moving on a circular track with a radius of 6 m. If the train's kinetic energy changes from 16 j to 80 j, by how much will the centripetal force applied by the tracks change by?

1 Answer
Mar 11, 2018

the centripetal force changes by four times of the initial value.

Explanation:

the centripetal force on the circular track is given by

f = m. v^2/r where m is mass ,r the radius and v the speed

initially it was f1 = 4kg. v^2 /(6m

therefore v^2 = (6/4) f1

The initial Kinetic energy = (1/2)m. v^2 = 16 joule(J)

Therefore (1/2) .4kg. (6/4) f1 = 16J

so f1 the initial centripetal force = 16/3 N

now if the kinetic energy is increased to 80 J the train will

speed up and f2 = (4/6 ).vel. ^2

thereby (1/2)m.vel.^2 = 80 J

putting up value of velocity ,we get

                  #(1/2). 4kg.( 6/4 ). f2 = 80J#

                                        #f2= 80/3 N#

so the change in centripetal force is 4 times the initial value.