A football player at practice pushes a 80 kg blocking sled across the field at a constant speed. The coefficient of kinetic friction between the grass and the sled is 0.30. How much force must he apply to the sled

The value is  

Explanation:

From the question we are told that

   The mass of the sled is  

  The  coefficient of friction is  

Generally the force that must be applied to the sled is equal to the frictional force experienced by the sled which is mathematically represented as

=>    

=>    

the answer would be c

f=ma newton's second law 7x8=56n