4. A 1.5 Kg pumpkin is dropped from a 2.5 meter high window on Halloween night. What is the pumpkin's speed right before it reaches the ground?

7.07 m/s

Explanation:

The conservation of energy states that energy cannot be destroyed or created but can be converted from one form to another. With this idea, we know that when the pumpkin is dropped, gravitational potential energy of the pumkin is converted to kinteic energy of the pumpkin. We can express this conversion as:

GPE = KE

mgh = 0.5mv^2 [Expand the formulae]

(1.5) (10) (2.5) = 0.5 (1.5) v^2 [Assuming g = 10]

0.75v^2 = 37.5

v = 7.07 m/s (3 sf)