A net force of 2×10⁴N is used to move a motorboat at a constant speed of 2.8m/s.how much power is develop?
Energy in = work done = Force times distance in direction of the force.
Power = energy per unit time
therefore
power = force times distance over time
but
distance over time = speed
so
power = Force * velocity in direction of force
in this case the units work out because Joules per second is Watts
and Joules is Newtons times meters
so
power in Watts = 2*10^4 * 2.8 = 5.6 * 10^4 Watts