Question

free fall
the state an object is in when gravity is the only force acting on it. near the
surface of a planetary body an object in free fall will have a constant
acceleration. this acceleration is referred to as the \free fall acceleration\. on
earth, the free fall acceleration is 9.8 m/s² down.
problem
a person throws a rock straight up into the air. at the moment it leaves the persons hand it is going 84 mph. when the rock reaches its pea
magnitude and direction of its acceleration? ignore air drag. express your answer using appropriate mks units.
speed = 0 m/s
acceleration = enter a number with units. dimensionally incorrect. please check the type or dimension of your unit. down

Explanation:

Step1: Analyze the motion

When the rock is in free - fall (ignoring air drag), the only force acting on it is gravity.

Step2: Recall the free - fall acceleration

Near the surface of the Earth, the free - fall acceleration \(g = 9.8\ m/s^{2}\) and its direction is downwards.

Answer:

\(9.8\ m/s^{2}\)