Question

At t=0, a constant force of 10 N is applied to a body of mass 5 kg starting at rest in outer space where there are no other forces. What is the power (in Watts) that the force delivers at t = 2 s?

Answer 1

Answer:

20 W.

Explanation:

Power is defined as the time rate oc change at which work is done.

Mathematically,

Power, P = workdone/time

Given:

vi = 0 m/s

F = 10 N

m = 5 kg

t = 2 s

F = ma

a = 10/5

= 2 m/s^2

Using equation of motion,

vf = vi + at

vf = 2 * 2

= 4 m/s

Workdone = potential energy, PE+ kinetic energy, KE

PE = 0

KE = 1/2 * m * v^2

= 1/2 * 5 * (4^2)

= 40 J

Power, P = 40/2

= 20 W.