A simple pendulum,3.0 m in length,is released with a push when the support string is at an angle of 20° from the vertical.If the initial speed of the suspended mass is 1.3 m/s when at the release point,what is its speed at the bottom of the swing? (g = 9.8 m/s²) A) 2.3 m/s B) 1.9 m/s C) 6.4 m/s D) 5.2 m/s E) 7.8 m/s

Question

Quizplus · Accepted Answer

The speed at the bottom can be found using energy conservation. The initial energy is the sum of kinetic and potential energy at the release point. At the bottom, all energy is kinetic. Calculate the initial potential energy using mgh, where h = 3 - 3cos(20°), and initial kinetic energy using 0.5mv². Set the sum equal to 0.5mv² at the bottom and solve for v. The correct speed is approximately 2.3 m/s.

A Simple Pendulum,3