posted by m2a on .
A pendulum consists of an object of mass m = 1.2 kg swinging on a massless string of length l = 259 cm. The object has a speed of 2.4 m/s when it passes through its lowest point. What is the greatest angle with the vertical that the string makes during the motion of the object?
This is geometry. Draw the figure.
Set mgh=1/2 mv^2, solve for h. That is the height to which the bob rises.
Draw the triangle. If I remember (in my head), Costheta=(l-h)/l
and you solve for the angle.
check that carefully.