Question

A tetherball leans against the smooth, frictionless post to which it is attached.The string is attached to the ball such that a line along the string passes through the center of the ball. The string is 1.20m long and the ball has a radius of 0.120mwith mass 0.380kg. What is the force the pole exerts on the ball?

Answer 1

Look at the angle the string makes with the pole.

.12/1.2=sinTheta

Now draw the vector diagram at the ball: mg downard, Tension along the string, and H the horizontal force.

h/mg=TanTheta

For this angle, you can use the small angle approximation that sine and tangent are equal.

H/mg=.1

Answer 2

.374