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

Answer:

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#