Answer:
To find the coefficient of kinetic friction, calculate the sled's change in kinetic energy, determine the net force, and use the work done to solve for the coefficient.
Step-by-step explanation:
To determine the coefficient of kinetic friction between the sled and the snow, we can use the concepts of Newton's second law and work-energy principle. Given a horizontal force of 30N pulling the sled, we start by finding the net work done to accelerate the sled to a speed of 2.8 m/s over a distance of 8.6 m.
The work-energy principle states that the net work done on an object is equal to the change in its kinetic energy. The sled started from rest, so its initial kinetic energy was zero. After being pulled 8.6 m, it has a kinetic energy of ½ × 20kg × (2.8 m/s)². We calculate this to find the work done by the net force.
Simultaneously, Newton's second law (F_net = m × a) allows us to calculate the net force (F_net) acting on the sled by subtracting the force of friction (friction force = coefficient of kinetic friction × normal force) from the pulling force. Since the ground is horizontal and there's no vertical acceleration, the normal force is equal to the weight of the sled (mg). Thus, the net force also equals the mass times the acceleration the sled experiences due to this force.
Once we equate the work done by the net force to the sled's kinetic energy, we can isolate the coefficient of kinetic friction and solve for it.
Key Steps:
Calculate the change in kinetic energy of the sled.
Determine the net force acting on the sled by accounting for the horizontal force applied and the force of friction.
Use the work done by the net force to solve for the coefficient of kinetic friction.