# The work of the traction force of a car that has passed with an unchanging universe, in essence

**The work of the traction force of a car that has passed with an unchanging universe, in essence, a path of 2 km is equal to 50 kJ, determine the force of friction.**

We translate the values from given to the SI system:

S = 2 km = 2000 m.

A = 50 kJ = 50,000 J.

According to Newton’s second law:

The acceleration acquired by the body as a result of the impact on it is directly proportional to the strength of this impact and inversely proportional to the body mass:

F = m * a

In our case, the following forces act on the body:

Ft + Fc = ma, Ft – traction force, Fc – drag force (friction force).

Let’s write in projections on the axis, taking into account that the body moves uniformly:

ОУ: Fт + Fc = 0

Fт = Fc

The work is equal to the pulling force multiplied by the displacement:

A = Fт * S

Let us express Ft from this expression and substitute it into Newton’s second law:

Fт = A / S

Fc = Fт = A / S

Substitute the numbers and determine the friction force:

Fc = A / S = 50000/2000 = 25 N.

Answer: the friction force is 25 N.