i think the answer u are looking for is b
 
        
                    
             
        
        
        
Given:
D=165 feet and the frequency of the motion is 1.6 revolutions per minute.
Solution:
The radius is half of the diameter.
The radius of the wheel is 82.5 feet.

As we know: 
Substitute the value of T in the above formula.

If the center of the wheel is at the origin then for  the rest position is
 the rest position is  .
.
This can be written as:
  
 
The actual height of the rider from the ground is:

The required equation is  .
.
 
        
             
        
        
        
Answer:
5 roots (answer C)
Step-by-step explanation:
Any polynomial should have in the Complex Number System, as many roots as the polynomial's degree.
In our case, since we are dealing with a polynomial of order 5 (degree 5), it should have 5 roots in the Complex Number System.
 
        
             
        
        
        
Look at the picture......