Question

A model train, with a mass of `7 kg`, is moving on a circular track with a radius of `6 m`. If the train's rate of revolution changes from `1/3 Hz` to `2/7 Hz`, by how much will the centripetal force applied by the tracks change by?

Answer 1

The change in centripetal force is `=45N`

Explanation:

The centripetal force is

`F=(mv^2)/r=mromega^2N`

The mass of the train, `m=(7)kg`

The radius of the track, `r=6m`

The frequencies are

`f_1=1/3=0.33Hz`

`f_2=2/7=0.286Hz`

The variation in centripetal force is

`DeltaF=F_2-F_1`

`F_1=mromega_1^2=mr*(2pif_1)^2=7*6*(2pi*0.33)^2=180.6N`

`F_2=mromega_2^2=mr*(2pif_2)^2=7*6*(2pi*0.286)^2=135.6N`

`DeltaF=F_1-F_2=180.6-135.6=45N`