A 1.0-kg ball is attached to a rigid vertical rod by means of two massless strings each 1.0 m long. The strings are attached to the rod at points d-1.0 m apart. The system is rotating about the axis of the rod, both strings being taut and forming an equilateral triangle with the rod, as shown in the figure. The tension in the upper string is 25 N.
a. Draw the free-body diagram for the ball.
b. What is the tension in the lower string?
c. What is the net force on the ball at the instant shown in the figure?
d. What is the speed of the ball?