A 3.0-kg block is dragged over a rough horizontal surface by a constant force of 16 N acting at an angle of 37° above the horizontal as shown. The speed of the block increases from 2 m/s to 3.8 m/s in a displacement of 5.5 m. What work was done by the friction force during this displacement?

The  value  is  

Explanation:

From the question we are told that

    The mass of the block is  

     The force is

     The  angle is  

     The first speed of the block is  

     The second  speed of the block is  

     The displacement is  

Gnerally from kinematic equation we have that

=>    

=>    

Generally the net force acting on the crate is mathematically represented as

Here   is the frictional force acting on the crate

So    

=>      

Generally the work done by  friction  during the displacement is mathematically represented as

=>    

=>    

i don't understand. explain it clearly