A ball is in a hot air balloon that starts from rest at t = 0 and accelerates upwards at 2m/s2. After 10s, the ball is dropped from the balloon.Draw ball's v - t graph:
From v - t graph velocity should increase linearly till t = 10s and then decrease linearly after t = 10s.
V at t = 20s
⇒ v = u + at
⇒ v = 0 + 2(10)
= 20 m/s
Ball then has an acceleration of -10 m/s2
∴Time when v = 0, will be
v = u + at
0 = 10 + (-10)t
⇒ 0 = 20 - 10t
⇒ 20 = 10t
⇒ t = 2s
∴At t = 12s, velocity will be ______
Velocity will be negative after t = 12 s
∴Correct option is c.