A model train, with a mass of $3 kg$ , is moving on a circular track with a radius of $5 m$ . If the train's kinetic energy changes from $9 j$ to $45 j$ , by how much will the centripetal force applied by the tracks change by?

Question

1301 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-01-24T10:33:43

The change in centripetal force is $=14.4N$

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 mass is $m=3kg$

The radius of the track is $r=5m$

The variation of centripetal force is

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

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

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

$=(2)/r*Delta KE$

$=2/5*(45-9)N$

$=14.4N$

A model train, with a mass of 3 kg3 kg, is moving on a circular track with a radius of 5 m5 m. If the train's kinetic energy changes from 9 j9 j to 45 j45 j, by how much will the centripetal force applied by the tracks change by?