Youngs Modulus and angular speed.

[Shlllink]

An amusement park ride consists of airplane-shaped cars attached to steel rods. Each rod has a length of 14.2 m and a cross-sectional area of 7.80 cm^2. Each car plus two people seated in it has a total weight of 1950 N.

When operating, the ride has a maximum angular speed of 7.50 rev/min. How much is the rod stretched then?

This problem does not give an angle or a radius of the circle, so I have two unknowns and can't get an answer.

So far I have

Tcos(theta) = mg

Tsin(theta) =mv^2/r

 

[rsk]

Your unknowns are r and theta

Are they related in anyway? (I'm assuming yes - they usually are, but I can't actually picture from your post whether I'm right. )

 

[Shlllink]

r is the radius of the circle created as the masses on the rods swing in a circle.

theta is the angle between the rod and its vertical support (perpendicular to the ground) as the masses swing outward




EDIT: What you said got me to thinking and I got the answer now. Thanks