A model train, with a mass of $3 kg$ , is moving on a circular track with a radius of $2 m$ . If the train's kinetic energy changes from $32 j$ to $12 j$ , by how much will the centripetal force applied by the tracks change by?

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Answer 1 · 2017-04-10T09:30:17

The centripetal force changes by $=20N$

The centripetal force is

$F=(mv^2)/r$

The kinetic energy is

$KE=1/2mv^2$

The variation of kinetic energy is

$Delta KE=1/2mv^2-1/2m u^2$

$=1/2m(v^2-u^2)$

The variation of centripetal force is

$DeltaF=m/r(v^2-u^2)$

$DeltaF=2m/r1/2(v^2-u^2)$

$=(2)/r*1/2m(v^2-u^2)$

$=(2)/r*Delta KE$

$=2/2*(32-12)N$

$=20N$

A model train, with a mass of 3 kg3 kg, is moving on a circular track with a radius of 2 m2 m. If the train's kinetic energy changes from 32 j32 j to 12 j12 j, by how much will the centripetal force applied by the tracks change by?