A ball A is thrown vertically upward with speed u . At the same instant, another ball B is released from rest at height h . At time t , the speed of A relative to B is (Assume both are in the air)

Question

A ball A is thrown vertically upward with speed u . At the same instant, another ball B is released from rest at height h . At time t , the speed of A relative to B is (Assume both are in the air) (A) u (B) u-2gt (C) √u2 - 2 g h (D) u-gt

Tardigrade Admin · Accepted Answer

From equation of motion, we have v = u + gt where u is initial velocity and t is time. For ball A , v A = u - gt For ball B , v B =0+ gt ∴ Relative speed <img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/6bd903ce90b1a0b8ce154a3519e2de2f-.png" />

Q. A ball $A$ is thrown vertically upward with speed $u$ . At the same instant, another ball $B$ is released from rest at height $h$ . At time $t$ , the speed of $A$ relative to $B$ is (Assume both are in the air)

$u$

$u - 2 g t$

$u^{2} - 2 g h$

$u - g t$

From equation of motion, we have
$v = u + g t$
where $u$ is initial velocity and $t$ is time.
For ball $A, v_{A} = u - g t$
For ball $B, v_{B} = 0 + g t$
$∴$ Relative speed

Q. A ball A is thrown vertically upward with speed u . At the same instant, another ball B is released from rest at height h . At time t , the speed of A relative to B is (Assume both are in the air)

u

u−2gt

u2−2gh​

u−gt

From equation of motion, we have v=u+gt where u is initial velocity and t is time. For ball A,vA​=u−gt For ball B,vB​=0+gt ∴ Relative speed

Q. A ball $A$ is thrown vertically upward with speed $u$ . At the same instant, another ball $B$ is released from rest at height $h$ . At time $t$ , the speed of $A$ relative to $B$ is (Assume both are in the air)

$u$

$u - 2 g t$

$u^{2} - 2 g h$

$u - g t$

From equation of motion, we have
$v = u + g t$
where $u$ is initial velocity and $t$ is time.
For ball $A, v_{A} = u - g t$
For ball $B, v_{B} = 0 + g t$
$∴$ Relative speed