An object has a kinetic energy of 8.8J, and a mass of 450g. How fast is the object moving?

The formula for KE is

We have everything we need to solve for the velocity, but we first have to convert the mass from grams to kg:

450 g = .450 kg

and we'll rearrange that and solve it for v before we do any math:

so

v = 6.3 m/s rounded to the correct number of sig fig's

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.