Question
A block of mass 4 kg is placed on a rough horizontal surface. When an impulse of 12Ns is given to the body it comes to rest by sliding a distance of 1-5m. Find the coefficient of friction. Take g = 10m/s2v.
Solution
Let 
be the coefficient of friction between block and horizontal surface.
The force of friction between block and horizontal surface is,
The retardation of block is,
Mass of block, m = 4 kg
Impulse given to block, I = 12Ns
Initial velocity of block, u = I/m = 3m/s
Here,
u = 3 m/s, v = 0
Acceleration,
Distance travelled, s = 1.5m
Now, using equation of motion,
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i.e.,
be the coefficient of friction between block and horizontal surface. The force of friction between block and horizontal surface is,
The retardation of block is,
Mass of block, m = 4 kg
Impulse given to block, I = 12Ns
Initial velocity of block, u = I/m = 3m/s
Here,
u = 3 m/s, v = 0
Acceleration,
Distance travelled, s = 1.5m
Now, using equation of motion,
i.e.,
