A model train, with a mass of $15 kg$ , is moving on a circular track with a radius of $6 m$ . If the train's kinetic energy changes from $40 j$ to $27 j$ , by how much will the centripetal force applied by the tracks change by?

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Answer 1 · 2018-01-27T02:27:36

$-4.3$ Newtons.

We know that the centripetal force is given by

$F_c = (mv^2)/r$

We also know that kinetic energy is $E= 1/2mv^2$ . We know that $2E = mv^2$ , or $v^2 = (2E)/m$ . Therefore:

$F_c = (m(2E)/m)/r$

$F_c = (2E)/r$

So

$DeltaF_c = (Delta 2E)/r$

Or

$DeltaF_c = (2(27))/6 - (2(40))/6$

$DeltaF_c = 9-40/3$

$DeltaF_c = -4.3 N$

Hopefully this helps!

A model train, with a mass of 15 kg15 kg, is moving on a circular track with a radius of 6 m6 m. If the train's kinetic energy changes from 40 j40 j to 27 j27 j, by how much will the centripetal force applied by the tracks change by?