T = mgcosQHow is tension related to circular motion in a vertical circle?

AI Thread Summary
Tension in a vertical circular motion is derived from the balance of forces acting on the mass, where the net radial force equals the mass times its acceleration. The equation T = ma - mgcosθ describes the relationship between tension (T), mass (m), gravitational force (mg), and the angle (θ) with respect to the vertical. The gravitational force can be split into two components: one along the tension line (mgcosθ) and one perpendicular to it. The resultant force equation, Fr = T - mgcosθ = 0, indicates that tension must counteract the component of weight acting along the line of tension. Understanding these relationships is crucial for analyzing motion in vertical circles.
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Homework Statement



A rock is whirled at the end of a rope in a vertical circle

Find a general expression fo the Tension

What is the magnitude of the total acceleration

Homework Equations





The Attempt at a Solution



\sumFr = ma = T + mgcos\theta

T = ma - mgcos\theta not sure

a = (T + mgcos\theta)/m not sure
 
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At an angle θ to the vertical, what is the component of the weight along the line of tension?
 
not sure what u mean
 
joemama69 said:
not sure what u mean

Draw the mass at angle θ to the vertical.


Can you split the weight mg into two components?
 
into two components, would that be the tangental compenent in the direction of the velocity and the second pointing towards teh center
 
joemama69 said:
into two components, would that be the tangental compenent in the direction of the velocity and the second pointing towards teh center

actually it points opposite to the velocity and away from the center. What are these two components in terms of the angle?
 
Component along line of tension ma = mgcosQ

how do i do tat for the velocity, do i integrate that
 
joemama69 said:
Component along line of tension ma = mgcosQ

how do i do tat for the velocity, do i integrate that

the component is mgcosθ.

So the T points towards the center and the mgcosθ points away from the center. What is the resultant force equal to ?
 
Fr = T - mgcosQ = 0
 
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