(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A 2.0 kg ball swings in a vertical circle on the end of an 80 cm-long string. The tension in the string is 20 N when its angle from the highest point on the circle is theta = 30.

A) What is the ball's speed when theta = 30?

B) What is the magnitude of the ball's acceleration when theta = 30?

C) What is the direction of the ball's acceleration when theta = 30? Give the direction as an angle from the r-axis.

2. Relevant equations

f=ma; a = v^{2}/r

3. The attempt at a solution

A) T-mgcos(theta)=mv^{2}/r; v=sqrt((t-gcos(theta))*r) which is 3.8 m/s (the correct answer)

I have no idea how to go about finding part b and c. The only thing I may know about part c is that I'll have to use arctan at some point.

Thanks for all the help, I really appreciate it :)

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# Homework Help: Magnitude/direction of the ball's acceleration

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