How does the static friction between the box and the carpet in Question 5 compare to the kinetic friction as the box is sliding across the carpet?
To compare the static friction and kinetic friction between the box and the carpet, we need to understand their definitions and how they differ.
Static friction refers to the force that opposes the initiation of motion between two surfaces in contact that are not currently moving relative to each other. In other words, it is the force that keeps the box from moving when you try to push it.
Kinetic friction, on the other hand, refers to the force that opposes the motion between two surfaces in contact when they are already in motion relative to each other. In the case of the box sliding across the carpet, kinetic friction is the force that acts to slow down the box's motion.
Now, to the comparison between static friction and kinetic friction:
1. Magnitude of force: The static friction force can vary up to a maximum value, known as the maximum static friction. The actual value of static friction will depend on the force applied to the box. Once the applied force to overcome static friction exceeds the maximum static friction, the box will start moving, and static friction will be replaced by the kinetic friction force. Kinetic friction usually has a constant magnitude, which is generally lower than the maximum static friction.
2. Direction: Both static and kinetic friction forces act opposite to the direction of the applied force. In the case of pushing a box horizontally, the friction forces act in the opposite direction to the pushing force.
3. Transition: The transition from static to kinetic friction occurs when the applied force reaches or exceeds the maximum static friction. Once the transition occurs, the box starts moving, and the friction force changes from static to kinetic. The transition is usually associated with a sudden decrease in force required to keep the box moving.
In summary, the static friction force acts to prevent motion between the box and the carpet until an external force overcomes it, while kinetic friction acts to resist the box's motion once it is already sliding. The magnitude of static friction can be greater than the magnitude of kinetic friction, but once the box starts sliding, the kinetic friction remains relatively constant.