A bullet of mass 0.1 kg moving horizontally with speed 400 m s^(-1) hits a wooden block of mass 3.9 kg kept on a horizontal rough surface. The bullet…

Question

A bullet of mass 0.1 kg moving horizontally with speed 400 m s^(-1) hits a wooden block of mass 3.9 kg kept on a horizontal rough surface. The bullet gets embedded into the block and moves 20 m before coming to rest. The coefficient of friction between the block and the surface is _______.

MARKS Content Team · Accepted Answer

Correct answer: (D) 0.25. Let the mass of the bullet be m and mass of the block be M. It is given that V=400 m s^(-1). By conservation of momentum, mV=(m+M)v ⇒0.1×400=(0.1+3.9)v ⇒v=10 m s^(-1) The force acting on the block f=μm'g⇒a=μg Using v'^2-v^2=-2aS ⇒ 0^2-10^2=2(-μg)(S) ⇒μ=100/(2×10×20)=0.25

A bullet of mass $0.1 kg$ moving horizontally with speed $400 m s^{- 1}$ hits a wooden block of mass $3.9 kg$ kept on a horizontal rough surface. The bullet gets embedded into the block and moves $20 m$ before coming to rest. The coefficient of friction between the block and the surface is _______.

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Relevant Questions

A bullet of mass 0.1 kg moving horizontally with speed 400 m s-1 hits a wooden block of mass 3.9 kg kept on a horizontal rough surface. The bullet gets embedded into the block and moves 20 m before coming to rest. The coefficient of friction between the block and the surface is _______.

Solution

Relevant Questions

A bullet of mass $0.1 kg$ moving horizontally with speed $400 m s^{- 1}$ hits a wooden block of mass $3.9 kg$ kept on a horizontal rough surface. The bullet gets embedded into the block and moves $20 m$ before coming to rest. The coefficient of friction between the block and the surface is _______.