Answer to Question #197509 in Physics for Andu

Question

21. The body, which is attracted by a constant force F = 20N, moves at a constant speed, on a horizontal surface. In these conditions we can say: A) the resultant force has the value 20N B) the friction force has the value 20N C) the friction force is zero D) no other forces act on the body

Answer 1

According to Newton's second law, if the body moves at constant speed, the net force (the sum of all forces acting on the body) is zero. So, if we have 20 N pulling, the force resisting is 20 N as well. So, the correct option is that the friction force has the value 20N.