A model train, with a mass of 24 kg, is moving on a circular track with a radius of 3 m. If the train's kinetic energy changes from 18 j to 21 j, by how much will the centripetal force applied by the tracks change by?

1 Answer
P dilip_k
Mar 5, 2016

2N

Explanation:

Mass of the train m= 24kg
The radius of circular path (r)=3m
Initial velocity,v_1
final velocity,v_2
Initial KE,=1/2mv_1^2
final KE,1/2mv_2^2
Change in KE =1/2mv_2^2-1/2mv_1^2=21-18=3J
Dividing both sides of this equation by radius (r)of circular path and multiplying both sides by 2 we have
mv_2^2/r-mv_1^2/r=2*3/r
We see that left side of the equation is the change in centripetal force
So The change in centripetal force is =2*3/r=2.3/3(N.m)/m=2N

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