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?

1 Answer
Dec 6, 2017

Answer:

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#