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## Homework Statement

Bob, who has a mass of 75 kg, can throw a 500 g rock with a speed of 30 m/s. The distance through which his hand moves as he accelerates the rock from rest until he releases it is 1.0 m.

## Homework Equations

a. What constant force must Bob exert on the rock to throw it with this speed?

b. If Bob is standing on frictionless ice, what is his recoil speed after releasing the rock?

## The Attempt at a Solution

Known

vi = 0

vf = 30 m/s

delta x = 1 m

[itex]v^2 = vi^2 + 2ax = a = 450 m/s^2[/itex]

[itex]F_{net} = m_{total} * a = (75 kg + 0.500 kg)*450 m/s^2 = 33975 N[/itex]

recoil have no idea.