It is said that Galileo dropped objects off of the Leaning Tower of Pisa to determine whether heavy or light objects fall faster. If Galileo had dropped a 5 kg cannonball from a height of 12 meters,

ΔP.E = - 588 J

Explanation:

The complete question is as follows:

It is said that Galileo dropped objects off the Leaning Tower of Pisa to determine whether heavy or light objects fall faster. If Galileo had dropped a 5.0-kg cannon ball to the ground from a height of 12 m, what would have been the change in PE of the cannon ball?

So, in order to calculate the change in Potential Energy of the cannon ball, we will use the general formula of Potential Energy as follows:

ΔP.E = mgΔh

where,

ΔP.E = Change in Potential Energy = ?

m = mass of cannon ball = 5 kg

g = acceleration due to gravity = 9.8 m/s²

Δh = Change in Height of Cannon Ball = Final Height - Initial Height

Δh = 0 m - 12 m = - 12 m

Therefore,

ΔP.E = (5 kg)(9.8 m/s²)(- 12 m)

ΔP.E = - 588 J

Negative sign shows decrease in Potential Energy

probably not if net force is zero

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.