Question

A bullet moving with a velocity of 100m/s pierce a block of wood and moves out with a velocityof 10 m/s. if the thickness of the block reduces to one half of the previous value

Answer 1

Answer:

Is this block of wood stationary ?

If so

loss of energy in block = F of friction time thickness

energy loss = (1/2)m (100)^2 - (1/2)m(10^2)

= (m/2)(9900)

If we only lost half as much then

(m/2)(100)^2 - (m/2)v^2 = (m/2)(4950)

v^2 = 5050

v = 71.1 m/s

Explanation:

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