Question

A model train, with a mass of `3 kg`, is moving on a circular track with a radius of `1 m`. If the train's kinetic energy changes from `21 j` to `36 j`, by how much will the centripetal force applied by the tracks change by?

Answer 1

To make it simple, lets find out the relation of kinetic energy and centripetal force with the things we know:

We know: `"K.E." = 1/2momega^2r^2`

and `"centripetal force"=momega^2r`

Hence, `"K.E" = 1/2xx"centripetal force"xxr`

Note, `r` remain constant in the course of the process.

Hence, `Delta"centripetal force" = (2Delta"K.E.")/r = (2(36-21)J)/(1m)=30N`