Abaseball with a mass of 0.15 kg is moving at a speed of 40.0 m/s. what is the baseball's kinetic energy from this motion?

The baseball's kinetic energy is 120 joules.

Explanation:

The kinetic energy is defined as:

 (1)

Where is the kinetic energy, m is the mass and v is the velocity.

The kinetic energy represents how much energy have an object as a consequence of its movement.

For the case of a baseball (m = 0.15 kg, v = 40.0 m/s):

But 1 j =

Hence, baseball's kinetic energy is 120 joules.

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.