a horizontal force of 100 N is required to push a box across a floor at a constant velocity.
A) what is the net force acting on the box?
B) how much is the friction force that acts on the box

Question

a horizontal force of 100 N is required to push a box across a floor at a constant velocity.
A) what is the net force acting on the box?
B) how much is the friction force that acts on the box

isaidavila · Answer

Because of the box is traveling at constant velocity , ie, is un balance, the net force is equal to zero.
The fricción force is equal to the push force.

isaidavila · Answer

Because of Newton's third law the sum of all forces is equal to the mass times  the acceleration 
F=ma where a= 0 because of the constant velocity.
Then the friction force is opposite to the direction of movement :
Push force= friction force.
Sorry for my english.