When a physics student exerts a 36N force to pull a 5.3 kg sled across the ground at a constant speed, the force of kinetic friction between the sled and the ground is also 36N. The force of kinetic friction acts in the opposite direction to the applied force, and both forces are equal in magnitude.
To find the force of kinetic friction between the sled and the ground, we need to consider Newton's second law and the concept of equilibrium.
1. Newton's second law: It states that the net force acting on an object is equal to the product of its mass and acceleration. In this case, the sled is moving at a constant speed, so its acceleration is zero. Therefore, the net force acting on the sled must also be zero.
2. Forces acting on the sled: The student exerts a force of 36N on the sled, which we'll call the applied force. The force of kinetic friction, which we're trying to find, acts in the opposite direction to the applied force.
3. Equilibrium condition: Since the sled is moving at a constant speed, the net force acting on it is zero. This means that the applied force and the force of kinetic friction must be equal in magnitude but opposite in direction.
4. Calculation: The force of kinetic friction can be calculated by setting it equal to the applied force. Therefore, the force of kinetic friction is 36N.