A model train, with a mass of $5 kg$ , is moving on a circular track with a radius of $9 m$ . If the train's kinetic energy changes from $70 j$ to $40 j$ , by how much will the centripetal force applied by the tracks change by?

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Answer 1 · 2017-06-10T14:28:02

The change in centripetal force is $=6.67N$

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 radius is $=9m$

The variation of centripetal force is

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

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

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

$=(2)/r*Delta KE$

$=2/9*(70-40)N$

$=6.67N$

A model train, with a mass of 5 kg5 kg, is moving on a circular track with a radius of 9 m9 m. If the train's kinetic energy changes from 70 j70 j to 40 j40 j, by how much will the centripetal force applied by the tracks change by?