Question

A model train with a mass of `5 kg` is moving along a track at `4 (cm)/s`. If the curvature of the track changes from a radius of `16 cm` to `2 cm`, by how much must the centripetal force applied by the tracks change?

Answer 1

0.35N

Explanation:

We have that:

• `m=5kg`
• `v=4 cm s^-1=0.04ms^-1`
• `r_1 =16cm = 0.16m`
• `r_2 = 2cm = 0.02m`

The centripetal force is given by:

`F = (mv^2)/r`

Thus we can work out the change in centripetal force:

`DeltaF = F_2-F_1=(mv^2)/r_2 -( mv^2)/r_1`

`=((5)(0.04)^2)/0.02-((5)(0.04)^2)/0.16=0.35N`