A model train, with a mass of 8 kg, is moving on a circular track with a radius of 2 m. If the train's kinetic energy changes from 8 j to 48 j, by how much will the centripetal force applied by the tracks change by?

1 Answer
Jun 9, 2016

I found that it changes of 40N

Explanation:

I can use the definition of Kinetic Energy: K=1/2mv^2
K_i=8=1/2*8v_i^2
v_i=sqrt(2)m/s
K_f=48=1/2*8v_f^2
v_f=sqrt(12)m/s

We know that centripetal force is: F_c=mv^2/r
so:
F_(ci)=mv_i^2/r=8(2)/2=8N
and:
F_(cf)=mv_f^2/r=8(12)/2=48N

DeltaF_c=48-8=40N