A model train, with a mass of $4 k g$ $4 kg$ , is moving on a circular track with a radius of $8 m$ $8 m$ . If the train's kinetic energy changes from $6 j$ $6 j$ to $0 j$ $0 j$ , by how much will the centripetal force applied by the tracks change by?

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Answer 1 · 2017-10-13T05:22:08

The change in centripetal force is $= 1.5 N$ $=1.5N$

The centripetal force is

$F = \frac{m v^{2}}{r}$ $F=(mv^2)/r$

The kinetic energy is

$K E = \frac{1}{2} m v^{2}$ $KE=1/2mv^2$

The variation of kinetic energy is

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

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

The mass is $m=4kg$

The radius of the track is $r=8m$

The variation of centripetal force is

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

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

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

$=(2)/r*Delta KE$

$=2/8*(6-0)N$

$=1.5N$

A model train, with a mass of 4 kg4kg4 kg, is moving on a circular track with a radius of 8 m8m8 m. If the train's kinetic energy changes from 6 j6j6 j to 0 j0j0 j, by how much will the centripetal force applied by the tracks change by?