Aman standing on the edge of a roof of a 20m tall building projects a ball of mass 100g vertically up with a speed of 10 ms^(-1) and simulaneously throws another ball of same mass vertically down with the same speed. Find the kinetic energy of each ball when they reach the ground (g= 10 ms^(-2))

Aman standing on the edge of a roof of a 20m tall building projects a

1.	Aman standing on the edge of a roof of a 20m tall building projects a ball of mass 100g vertically up with a speed of 10 ms^(-1) and simulaneously throws another ball of same mass vertically down with the same speed. Find the kinetic energy of each ball when they reach the ground (g= 10 ms^(-2))
Answer» Solution :Both the two BALLS reach the ground with the same velocity `h=20m, m= 100g= 10^(-1) kg, u= 10 ms^(-1)` `v^(2)- u^(2)= 2gh` `v^(2)= u^(2) + 2gh = 10^(2) + 2 xx 10 xx 20 = 500` K.E. of each ball `=(1)/(2) mv^(2) = (1)/(2) xx 10^(-1)xx 500 = 25J` `THEREFORE` K.E of balls = 25J