Q. A body is thrown vertically upward from a point ‘A’ 125m above the ground. It goes up to a maximum height of 250 m above the ground and passes through ‘A’ on its downward journey. The velocity of the body when it is at a height of 70m above the ground is (g = 10 m/s^{2})

(a) 20 m/s

(b) 50 m/s

(c) 60 m/s

(d) 80 m/s

Ans:(c)

Sol: For downward journey ,

$\displaystyle v^2 = u^2 + 2 g h $

$\displaystyle v^2 = 0 + 2 g (250-70) $

v = 60 m/s