PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A bob of mass 0.50kg is suspended by a light, inextensible string of length 1.20m to form a simple pendulum. The bob is pulled aside so that the string makes an angle of 30∘ with the vertical and is then released from rest. Neglect air resistance and the mass of the string.
(i) Calculate the speed of the bob as it passes through the lowest point of its path. (Take g=9.8ms−2.)
(ii) After passing the lowest point, the bob rises on the other side of the swing. Determine its speed when the string again makes an angle of 20∘ with the vertical.