# Physics

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A bullet of mass 0.02kg is fired at a speed of 500m/s towards a fixed wooden block of thickness 10cm. The bullet penetrates the block and emerges with a speed of 200m/s.

a) Find the average retarding force on the bullet when it is passing through the block.
b) Estimate the time required for the bullet to pass through the block.
c) If the block is not present, how long does the bullet take to travel the same distance?

• Physics -

a)
mass, m = 0.02 kg
Distance, S = 10 cm = 0.01 m
initial velocity, u = 500 m/s
final velocity, v = 200 m/s
Acceleration = (v²-u²)/2S m/s²

b)
v=u+at
solve for t.

c)
Time to travel 10 cm without resistance,
t0 = S/u

• Physics -

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