Answer:

Explanation:
From the question we are told that:
Time 
Generally the Period is given as

Therefore difference in frequency dF



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 />
Explanation:
Linear acceleration is a type of acceleration of a body along a straight path or line.
Acceleration is defined as the rate of change of velocity with time.
Acceleration = 
There are different types of acceleration .
- linear acceleration is used to describe the rate of change of velocity of a body along a straight path with time.
- centripetal acceleration is the rate of change of velocity of a body traveling along a circular path with time. It is directed towards the center.
- Angular acceleration is the rate of change of angular velocity.
Learn more:
Acceleration brainly.com/question/3820012
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The air pushes the engine with an equal force in the opposite direction.
Whenever force is used there is an opposite yet equal affect.