A $$ping-pong$$ ball of mass m is floating in air by a jet of water emerging out of a nozzle. If the water strikes the $$ping-pong$$ ball with a speed v and just after collision water falls dead, the rate of mass flow of water in the nozzle is equal to:

Question

Infinity Learn · Accepted Answer

The impact force F $$=$$ Δp $$/$$ Δt where Δp $$=$$ change of momentum of water of mass Δm striking the ball a speed v during time Δt . Since water falls dead after collision with the $$ping-pong$$ ballΔp $$=$$ Δmv ⇒  F $$=$$ v $$($$Δm $$/$$Δ$$t)$$ upward on the ballWhere Δ$$m/$$Δt $$=$$ rate of mass of water in the nozzle.Since the ball is in equilibrium.F $$-$$ mg $$=$$ $$0$$  ⇒ F $$=$$ mg ⇒  V . $$($$Δ$$m/$$Δ$$t)$$ $$=$$ mg ⇒  Δ$$m/$$Δ$$t=mg/VHence$$ (3) is the corerct choice

A ping-pong ball of mass m is floating in air by a jet of water emerging out of a nozzle. If the water strikes the ping-pong ball with a speed v and just after collision water falls dead, the rate of mass flow of water in the nozzle is equal to:

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