Posted by Cody on Thursday, September 22, 2011 at 3:40pm.
One end of a cord is fixed and a small 0.470kg object is attached to the other end, where it swings in a section of a vertical circle of radius 2.50 m as shown in the figure below. When θ = 21.0°, the speed of the object is 4.70 m/s. At this instant, find each of the following.
(a) the tension in the string
(b) the tangential and radial components of acceleration
(c) the total acceleration
I have the tension and it is 8.48N and I have the radial component of acceleration. I can't figure out how to get the tangential component of acceleration.
Please help and thank you.

Physics  bobpursley, Thursday, September 22, 2011 at 4:01pm
Tangential acceleration is due to gravity. So you are looking for the component of gravity in the direction of the tangent.
tangential acceleration= g*sinorcosine 21
I don't know how your angle is measured, but you will need sin21 or cos21. Draw the figure. 
Physics  Cody, Thursday, September 22, 2011 at 4:14pm
Thank you very much. I used sin21 and it was right.