Question

A body is moving vertically upwards.Its velocity changes at a constant rate from $50m{s}^{-1}$ to $20m{s}^{-1}$ in 3s.What is its acceleration?

Answer 1

Given
initial velocity(u) = $50m{s}^{-1}$
final velocity = $20m{s}^{-1}$
time = 3 seconds

applying $v=u+at$

$20=50+at$

$-30=3a$
acceleration,$a=-10m{s}^{-2}$