Law of conservation of energy

Energy is either created or destroyed but converts from one form to another.

At point A:

A body of mass ‘m’ is thrown up with a velocity ‘u’ from the ground level. Let us take the point as A. therefore it has only kinetic energy and potential energy is equal to ‘0’ at A.

Energy at A

K.E = ½ mu2

P.E = 0.

Total Energy = ½ mu2

At point B:

Now let the velocity of a body after reaching a height ‘x’ from the ground be ‘u’. Let us take that point as B.

So it is

K.E at x is ½ m (u’)2

P.E is mgx

Total Energy = ½ m (u’)2  + mgx.

At point c:

Now let us assume the body has reached the maximum height of ‘Hmax’. Let this point be ‘C’.

Here P.E is mgHmax

K.E is 0

At C i.e., at maximum Height

K.E = 0

P.E = mgHmax

According to law of conservation of energy at A, B & C must be equal. As, the gravitational force is a conservative force.

TA = TB = TC

½ mu2 = ½ mu2 + mgx = mgHmax