Physics

The work done by the frictional force causes the block to come to rest, which means all its initial kinetic energy is used to overcome friction. The work-energy principle states that the work done by the friction force equals the change in kinetic energy.

 

Calculate the initial kinetic energy

The initial kinetic energy of the block is given by:

 

Where:

(mass of the block),

(initial velocity).

 

So, the block has an initial kinetic energy of .

 

Use the work done by friction

The work done by the frictional force is equal to the frictional force times the distance over which it acts:

 

Since the block comes to rest, the work done by the friction force is equal to the negative of the initial kinetic energy:

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