A bullet of mass 20 g travelling horizontally with a speed of 500 m/s passes through a wooden block of mass 10.0 kg initially at rest on a level surface. The bulet emerges with speed of 100 m/s and the block slides 20 cm on the surface before coming to rest. Find the friction cioefficient between the block and the surface figure.

Answer

A

Explanation

mass of bullet `m=0.02 k`
`Initial velocityof bullet V_1=500m/sec`
Mass of blcok M=10kg `
Initial velocity of block `=U_2=0`
`FiN/Al velocity of bullet =10 m/sec
`=v^1
Let the fiN/Al velocityi of block when the bullet consevation of energy.
`mv_1+mv_2=mv+Mv^1` ltbr `rarr 0.02xx500=0.02xx10++10xxv^1`
`rarr v^1=0.8m/sec`
After moving distance 0.02 m it stops.
`rarr Change in K.E. =Work done
`rarr 0-(1/2)xx10xx(0.8)^2=Mxx10xx10xx0.2`
`rarr M=0.16`