Question

A 45 kg swimmer starting from rest can develop a maximum speed of 12 m/s over a distance of 20 m. How much net force must be applied to do this?

Answer 1

Wnet = net work (done by the net force)
KE = kinetic energy = (1/2)mv2
m = 45 kg
vo = 0 m/s (starts at rest)
vf = 12 m/s (final speed)