Answer:
Explanation:
In order to measure the coefficient of friction , we apply external force to move the body . When external force comes in motion , we adjust the external force so that it moves with zero acceleration or uniform velocity . In this case external force becomes equal to kinetic frictional force and then net force becomes zero because
net force = mass x acceleration = m x 0 = 0
Now frictional force = μ mg where μ is coefficient of kinetic friction
so F = μ mg where F is external force applied
μ = F / mg
Hence , to make external force equal to frictional force , it is necessary to make acceleration of body zero .
