A model train, with a mass of $32 k g$ $32 kg$ , is moving on a circular track with a radius of $9 m$ $9 m$ . If the train's kinetic energy changes from $18 j$ $18 j$ to $27 j$ $27 j$ , by how much will the centripetal force applied by the tracks change by?

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Answer 1 · 2017-07-24T12:39:39

The centripetal force change by $= 2 N$ $=2N$

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 radius is $=9m$

The variation of centripetal force is

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

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

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

$=(2)/r*Delta KE$

$=2/9*(27-18)N$

$=2N$

A model train, with a mass of 32 kg32kg32 kg, is moving on a circular track with a radius of 9 m9m9 m. If the train's kinetic energy changes from 18 j18j18 j to 27 j27j27 j, by how much will the centripetal force applied by the tracks change by?