A weight-lifter raises a 2000 N weight through a vertical height of 2.0m in 0.80 s. What useful power does he develop in doing this?
A
800 W
B
3200W
с
4000 W
D
5000W

D. 5000W

Explanation:

Given the following data;

Force = 2000N

Distance = 2m

Time = 0.8s

To find the power;

First of all, we would determine the workdone by the weightlifter

Workdone = force * distance

Workdone = 2000 * 2

Workdone = 4000N

Now, we can find the power using the formula;

Power = workdone/time

Substituting into the equation, we have

Power = 4000/0.8

Power = 5000 Watts

If we drop an object near the surface of the Earth, it falls towards the surface with constant acceleration, g. This means that, as it falls, it speeds up (specifically, its speed increases by 9.8 m/s for each second it is falling). If we measure the distance fallen, we find that the object has dropped 4.9 meters after 1 second, 18.6 m after 2 sec, 44.1 m after 3 sec, etc. The equation for the distance fallen after t seconds is