a. The given friction force of 24 N is a kinetic friction force. This is because the problem states that the gardener is pushing the mower to move it at a constant speed. In such a scenario, the friction force opposing the motion is kinetic friction. Kinetic friction occurs when two surfaces are sliding or moving relative to each other.
b. To calculate the coefficient of friction, we need to use the equation:
Friction force = coefficient of friction * Normal force
The normal force is the force exerted by the ground on the mower, which is equal to the weight of the mower. The weight can be calculated using the formula:
Weight = mass * gravitational acceleration
Given:
mass = 23 kg
gravitational acceleration ≈ 9.8 m/s²
Weight = 23 kg * 9.8 m/s² = 225.4 N
Now we can substitute the values into the equation for the friction force:
24 N = coefficient of friction * 225.4 N
Dividing both sides of the equation by 225.4 N, we get:
coefficient of friction = 24 N / 225.4 N
Simplifying this expression gives us:
coefficient of friction ≈ 0.1067
Therefore, the coefficient of friction between the mower and the ground is approximately 0.1067.