Answer:

Forces usually cannot be seen but their effects can. Nothing moves, changes speed, stops or changes direction without force. Heavier objects need more force to get them to move or change direction. Friction is a force that slows down the motion of a moving object.

Explanation:

An object is thrown straight up from the top of a building h feet tall with an ... model to determine how long it takes for the object to reach various heights. In this case, we set the equation equal to zero because the height of the ground is zero.