A model train with a mass of #2 kg# is moving along a track at #36 (cm)/s#. If the curvature of the track changes from a radius of #6 cm# to #3 cm#, by how much must the centripetal force applied by the tracks change?

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Answer 1 · 2017-03-05T15:42:36

#4.32N#

Put the values we have into SI units:

#36cms^-1 = 0.36ms^-1#
#6cm = 0.06m#
#3cm = 0.03m#

The equation for centripetal force is

#F = (mv^2)/r#

so the change in centripetal force is

#DeltaF = (mv^2)/r_2 - (mv^2)/r_1#

Plug in the values we are given,

#DeltaF = (2 xx 0.36^2)/0.03 - (2 xx 0.36^2)/0.06#

#= 8.64 - 4.32 = 4.32N#