A curve ball is a type of pitch in which the baseball spins on its axis as it heads for home plate. If a curve ball is thrown at 33.1 m/sm/s (74.0 mphmph) with a spin rate of 35 rev/srev/s, how many revolutions does it complete before reaching home plate

19.35 revolutions.

Explanation:

Let the home plate is 18.3 m (60 ft) from the pitching mound and that the baseball travels at a constant velocity.

Given that,

Velocity of ball = v = 34.5 m/s

Spin rate of ball = 26 revolutions/s

Distance between home plate and pitching mound = s = 18.3 m

We need to find the number of revolutions it complete before reaching home plate. It can be calculated as follows:

So, there are approx 19.35 revolutions.

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.