Aball is dropped off of a tall building and falls for 2 seconds before landing on a balcony. a rock is then dropped from the top of the building and falls for 4 seconds before landing on the ground. how does the final speed (meaning the speed it had just before landing) of the rock compare to the final speed of the ball?

Using the formula Final speed = initial speed + gravity * time, we can compare the results.

Being gravity approximately 9.8 m/s^2, and being both the rock and the ball dropped, we can assume that the initial speed of both is zero, so:

Ball: 9.8m/s^2 * 2s = 18.6 m/s
Rock: 9.8 m/s^2 * 4 = 37.2 m/s

The speed of the rock is the double of the speed of the ball at the moment just before landing, because it has been dropped in a greater height than the ball, allowing the rock to reach a greater speed than the ball.

This is what a calorimeter is used for simpler ex, to measure calories in food.