You drop a ball straight off a cliff. If it hits the group 4 s later what is its velocity

So I will not straight out give you the answer, I will tell you how to get it.

Explanation:

Acceleration due to gravity causes a falling object to pick up speed as it travels. Because a falling object’s speed is constantly changing, you may not be able to measure it accurately. However, you can calculate the speed based on the height of the drop; the principle of conservation of energy, or the basic equations for height and velocity, provide the necessary relationship. To use conservation of energy, you must balance the potential energy of the object before it falls with its kinetic energy when it lands. To use the basic physics equations for height and velocity, solve the height equation for time, and then solve the velocity equation.