How to Calculate the Horizontal Force by Rolling Friction?

Firstly, in order to determine the horizontal force, we need to calculate the work done by the friction force. The work done by a force can be calculated using the following formula:

Work Done = Force * Distance * Cosine of Angle

According to the principle of work-energy, the work done on an object is equal to its change in kinetic energy. Since the trailer comes to rest, its kinetic energy becomes zero. The only form of energy it had was kinetic energy when it was in motion. We can calculate the kinetic energy of the trailer when it was moving using the formula:

Kinetic Energy (KE) = 0.5 * Mass * Velocity^2

By substituting the values of mass (250 kg) and velocity (20 km/h converted to m/s), we can find the kinetic energy of the trailer at that point.

Next, we can use the obtained kinetic energy to solve for the friction force by dividing the work done (change in kinetic energy) by the distance over which the force is applied (85 meters):

Friction Force (F) = Work Done / Distance

By performing the calculations, you can determine the constant horizontal force created by rolling friction that causes the trailer to stop. In this case, the approximate value of the horizontal force is 81.7 N.

Understanding the relationship between work, energy, and forces is crucial in solving such physics problems. This method allows you to analyze the dynamics of the system and calculate the forces involved accurately.