The gravitational force on the car is the force popularly known
as the car's "weight". Its magnitude is
(9.8 m/s²) times (the car's mass, in kilograms) .
The unit of this quantity is [newton] .
Power is the rate work done given by dividing work done by unit time. It is measured in watts equivalent to J/s.
In this case the force by the student is mg = 490 N (taking g as 9.8m/s²)
Work done is given by force × distance,
Therefore, Power =(force × distance)/ time, but velocity/speed =distance/time
Thus, Power = force × speed/velocity
= 490 N × 1.25
= 612.5 J/S (Watts)
Hence, power will be 612.5 Watts.
