Please help me with this physics problem! I been stuck for a very long time! thanks!

Question

http://www.webassign.net/sercp/p7-52.gif

A 2-kg ball revolves in a horizontal circle as shown at a constant speed of 1.5 m/s. Knowing that L=600 mm(length of the string attached to the ball), determine (a)the angle deta that the cord forms with the vertical and (b) the tension in the cord. Please help thanks so much!

Answer 1

(b) tension = centripetal force

therefore F = m x v2(square)/r

            = 2x1.5x1.5/(600x0.001)

            = 7.5 N

for (a) i don't know how to calculate   unless i see the picture. But you can use v x cos angle or v x sin angle something like that.