Question

A 10 kg rock that has been dropped from a 60 meter high cliff experiences an average force of air resistance of 30 N. Calculate the KE at the bottom of the fall.

Answer 1

Answer:

4086 J

Explanation:

The potential energy is transformed to kinetic energy less the frictional energy. Potential energy= mgh where m represent mass, g is acceleration due to gravity and h is the height of cliff

Since we have force of air resistance, work done due to air resistance will be product of force and distance

$mgh-Fh= 0.5mv^{2}= KE$

Substituting 10 Kg for m, 9.81 for g and 60 m for F then the kinetic energy at the bottom will be

KE= 10*9.81*60- (30*60)=4086 J