Hello!!!

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Given,

Force F=100N

mass=3kg

Coefficient of friction=μ  = 1/4

As we know,F=ma

a=F/m

a=100/3 m/s^2

acceleration=100/3 m/s^2

frictional force f=μ ma

therefore f=1/4*3*100/3

f=25N

Frictional force f=25N

Hope it helps!!!!!!