A 4 g bullet is fired horizontally with a speed of 300m/s into 0.8 kg block of wood at rest on a table. If the coefficient of friction between block and table is 0.3, how far will the block slide approximately?

Momentum:

p₁ = m₁v₁

p₂ = m₂v₂

p₃ = (m₁ + m₂) v

p₁ + p₂ = p₃

v = p₁ + p₂ / (m₁ + m₂)

friction:

F = μ (m₁ + m₂) g = (m₁ + m₂) a ⇒ a = μg

equations of motion:

v = at = μgt ⇒ t = v/μg

x = 1/2 at² = 1/2 μg * v² / (μg) ² = 1/2 v² / μg

v₁ = 300 m/s

v₂ = 0 m/s

m₁ = 0.004 kg

m₂ = 0.8 kg

μ = 0.3

g = 9.81 m/s²

x = displacement