Q.
A truck starts from rest and accelerates uniformly at 2.0ms−2. At t=10s, a stone is dropped by a person standing on top of the truck (6m high from the ground). What is the velocity of the stone at t=11 s? (Take g=10ms−2)
Velocity of car (at t=10s ) =0+2×10=20ms−1
By the first law, the horizontal component of velocity is 20ms−1 throughout.
Vertical component of stone (at t=11s) =0+(10×1)=10ms−1 ⇒ Velocity of stone at 11th sec=202+102=500 =22.4ms−1