a head ball of mass 600g is thrown vertically upwards from ground level and reaches the maximum height of 20metres.calculate the initial velocity of the ball

What's a head ball?

Anyway the mass doesn't matter.
2 * 9.8 * 20 =vo^2 so
vo = Sqrt(2*9.8*20)

To calculate the initial velocity (u) of the ball, we can use the kinematic equation for vertical motion:

v^2 = u^2 + 2as

Where:
v = final velocity (which is 0 m/s at the maximum height, as the ball momentarily stops before falling back down)
u = initial velocity
a = acceleration (in this case, due to gravity, -9.8 m/s^2)
s = displacement (the maximum height, which is 20 meters)

Substituting these values into the equation, we can solve for u:

0^2 = u^2 + 2(-9.8)(20)

0 = u^2 - 392

Rearranging the equation, we can solve for u:

u^2 = 392

Taking the square root of both sides, we get:

u = ± √392

Calculating the square root of 392, we get:

u ≈ ± 19.8 m/s

Since the ball is thrown vertically upwards, the initial velocity is positive. Therefore, the initial velocity of the ball is approximately 19.8 m/s.