Question

1. explain how friction keeps a nail in place in a block of wood. if you try to pull out the nail, which way does the friction act?

Explanation:

When a nail is hammered into wood, the rough surfaces of the nail and the wood create friction. This friction resists the nail from moving. When trying to pull out the nail, friction acts in the opposite direction of the pulling force (i.e., downward, opposing the upward motion of pulling).

Answer:

Friction between the nail and wood's rough surfaces holds the nail. When pulling, friction acts opposite to the pulling direction (downward).