# 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

initially it was

therefore

The initial Kinetic energy

Therefore

so **f1** the initial centripetal force

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

speed up and

thereby

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.