A school bus is being pulled along a rough road at a constant speed by a rope attached to a moving tractor. The rope is parallel to the ground. The mass of the school bus is 100 kg, and the coefficient of kinetic friction between the road and school bus is 0.680. Find the tension in the rope.
The first step is to draw a free-body diagram of the school bus. There are three forces acting on the bus: the tension force in the rope (T), the force of gravity (mg), and the force of friction (Ff). Since the bus is moving at a constant speed, we know that the net force on the bus is zero. Therefore, the tension force in the rope must be equal and opposite to the force of friction.
Ff = μkmg
Ff = 0.680 × 100 kg × 9.81 m/s^2
Ff = 667.08 N
Therefore, the tension force in the rope is also 667.08 N.