A model train with a mass of 1kg is moving along a track at 6cms. If the curvature of the track changes from a radius of 8cm to 9cm, by how much must the centripetal force applied by the tracks change?

1 Answer
Jul 27, 2016

Let us apply the definition of centripetal force.

Explanation:

Centripetal force is exerted on curve trajectories to maintain their curvature; it is directed toward the center of the curve, and it is defined by:

F=mv2R

With a radius of 8 cm, the centripetal force values:

F1=mv2R21=1 kg(0.06 m/s)20.08 m=4.5102 N

where we have used SI units.

Now, with a radius of 9 cm, the centripetal force will decrease. Assuming that mass and speed are constant:

F2=mv2R22=1 kg(0.06 m/s)20.09 m=4.0102 N

The explanation is very easy: the bigger the circle which the train describes is, the easier it is to maintain it on its trajectory, and the less force you must apply.