Question

A person is dragging a 15 kg box along flat ground using a length of rope. The rope is at angle of 30° to the horizontal and the person is pulling with a force of 58 N.

Work out the coefficient of kinetic friction between the box and the ground.​

Answer 1

Step-by-step explanation:

To find the coefficient of kinetic friction, we need to use the formula:

coefficient of kinetic friction = force of kinetic friction / normal force

First, let's find the force of kinetic friction. Since the box is being pulled at a constant velocity (not accelerating), the force of kinetic friction is equal and opposite to the force of the person pulling the box:

force of kinetic friction = force of person pulling = 58 N

Now, let's find the normal force, which is the force exerted by the ground on the box perpendicular to the surface. Since the box is not moving up or down, the normal force is equal to the weight of the box:

normal force = weight of box = mass x gravity = 15 kg x 9.81 m/s^2 = 147.15 N

Finally, we can use these values to calculate the coefficient of kinetic friction:

coefficient of kinetic friction = force of kinetic friction / normal force = 58 N / 147.15 N = 0.394

Therefore, the coefficient of kinetic friction between the box and the ground is 0.394.