Question

A pendulum is used in a large clock. The pendulum has a mass of 2kg. If the pendulum is moving at a speed of 2.9 m/s when it reaches the lowest point on its path, what is the maximum height of the pendulum?

Answer 1

Answer : Maximum height of the pendulum is 0.43 m

Explanation :

Given that,

Mass of the pendulum, m = 2 kg

Speed of the pendulum, v = 2.9 m/s

When it reaches the lowest point on its path, the potential energy at the highest point is equal to the kinetic energy at the lowest point.

i.e.

$KE=PE$

$\dfrac{1}{2}mv^2=mgh$

h is the height of the pendulum.

$h=\dfrac{v^2}{2g}$

$h=\dfrac{(2.9\ m/s)^2}{2\times 9.8\ m/s^2}$

$h=0.43\ m$

Hence, this is the required solution.                              

Answer 2

You first us 1/2(mv^2) to solve for the potential energy and then put that in to PE=m*g*h and solve for hight