Question

The angle b/w frictional force and instantaneous velocity of a body moving over a rough surface is... ?? REPLY SOON PLEASE....

Answer 1

Angle between friction and instantaneous Velocity of an object moving over a rough surface is 180°

Let's consider a block of mass m moving over the rough surface along x axis.

So, Velocity vector will be :

$\boxed{ \rm{ \vec{v} = v \: \: \hat{i}}}$

Let coefficient of kinetic friction be $\mu$.

Frictional Force vector will be:

$\boxed{ \rm{ \vec{f} = \mu (mg) \: \:( - \hat{ i})}}$

Hence , the frictional force and Instantaneous Velocity is directed opposite to one another , such that friction can oppose the Velocity vector