A block is pushed across a rough horizontal surface from point A to point B by a force P. The magnitude of the force of friction acting on the block between A and B is 1.2 N and points A and B are 0.5 m apart. If the kinetic energies of the block at A and B are 4.0 J and 5.6 J, respectively, how much work is done on the block by the force P between A and B

The workdone by P is

Explanation:

Generally workdone is mathematically represented as

Where F is the force and d is the distance

  The total workdone = (Workdone by Force P + Workdone by frictional force )

The difference in kinetic energy

Substituting 5.6 J for and 4.0 J for

This change in kinetic energy of the block = The total kinetic energy

       The workdone by the frictional force is

the negative sign shown that the force is moving in the opposite direction

substituting 1.2 N for  and 0.5 m for d

Making Workdone by Force P the subject in the above equation we

            Workdone by Force P () = The total workdone()  -

Substitution values

number of electrons for neutral cl

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