A model train, with a mass of 6 kg, is moving on a circular track with a radius of 4 m. If the train's kinetic energy changes from 24 j to 42 j, by how much will the centripetal force applied by the tracks change by?

1 Answer
Feb 17, 2016

\deltaF_c=9N

Explanation:

Given that we have the involvement of Kinetic energy and centripetal force.
Kinetic energy is given by the equation K=1/2mv^2 and centripetal force by equation F_c=mv^2/r
From both equations, it can be seen that equation of kinetic energy can be substituted into the equation of centripetal force, and the equation would be F_c=2K/r

Given that we have to find just the change in the centripetal force, so \deltaF_c=2/r\deltaK=2/r(K_f-K_i)

K_f=42J and K_i=24J, r=4m
So, substituting into the equation \deltaF_c=cancel{2}/cancel{4}^2*(42-24)=18/2=9N

So the change in the centripetal force is given as above.