A body of mass 2 kg is thrown vertically upwards with an initial velocity of 20 m/s. What will be its P.E. at the end of 2 seconds? Take g = 10 m/s2
There is small mistake as the value of g has to be taken as negative as the ball is going up.
Energy is equal to the work done by a body.In this case work is being done against gravity i.e the formula for the work done= mgh.
We know the mass(2kg) and the value of g(10m/s), all we need to find is the height i.e the distance covered by the body.
We know that -
s=ut - 1/2at^2
s= 20*2 - 1/2*10*2*2
s= 40 - 1/2*40
s=40- 20
s=20m
Now, as we have got the value of h we only need to put the values in the formula = mgh
= mgh
= 2*10*20
=20*20
=400J
This means that the potential energy possessed by the body after 2 seconds is 400J.