Question

A body of mass 2kg is thrown upward with initial velocity of 20m/s. After 2 second in kinetic energy will be ?

Answer 1

A body of mass 2 kg is thrown upward with untill velocity of 20 m/sec . we have to find kinetic energy after 2 second .

first of all, we should find velocity of body after 2 sec. use formula ,v = u + at
u = 20 m/s [ upward direction ]
a = g m/s² [ downward direction]
t = 2 sec

so, v = 20 + (-g) × 2 = 20 - 10 × 2 = 0m/s
after 2 second velocity of body becomes zero.
but we know kinetic energy = 1/2 m v²
so, kinetic energy will be zero after 2 sec.