To move the bar evenly, a force of 10 N was applied. What is the friction force if a force of 20 N is applied?

F1 = 10 N.

F2 = 20 N.

Ftr -?

According to 1 Newton’s law, a body can be in a state of uniform rectilinear motion or a state of rest when no forces act on it or the action of forces is compensated.

Before the body does not move, the resting friction force acts on it, which is equal to the force with which the body is pulled. As soon as the static friction force reaches its maximum value and the horizontal force is greater, the body will begin to move. When moving, a sliding friction force acts on the body.

With the horizontal action of the force F1 = 10 N, it is compensated by the sliding friction force Ftr, the value of which is determined by the formula: Ftr = μ * m * g, where μ is the coefficient of friction between surfaces, m is the body mass, g is the acceleration of gravity.

As can be seen from the formula, the sliding friction force Ffr depends only on the body mass m and the friction coefficient μ, and does not depend on the value of the force F acting on it.

Ftr = 10 N.

Answer: when moving, a sliding friction force Ftr = 10 N. acts on the body.