Speed is the time rate at which an object is moving along a path, while velocity is the rate and direction of an object's movement.
Given:
The mass of the ball is

The speed of the ball is

Required: calculate the kinetic energy of the baseball
Explanation: to calculate the kinetic energy of a body we will use the formula as

first, we convert velocity from mi/h into m/s.
we know that

and

then the velocity is

now plugging all the values in the above formula, we get

Thus, the kinetic energy of the baseball is
Provided the projectile is landing at the same elevation as it is launched from, it is 45 degrees
The question isn't clear enough, I think it ask us to calculate the linear speed of a point at the edge of the DVD.
Now let's imagine we're a point at the edge of the DVD, we're undergoing a circular motion. Each minute we will complete a circular track 7200 times, now we need to know the distance we travel each turn. The perimeter of the DVD, a circular object is:

Know recall that:

We now need to know how much distance is traveled during a minute or 60 seconds:

Finally we divide this result with t=60 seconds:


Where the distance units were named units as the length unit is not specified in this exercise.<span />