Question

A pendulum has a mass of 1.5 kg and starts at a height of 0.4 m if it is released from rest how fast is it going when it reaches the lowest point of its path?

Answer 1

The speed of the pendulum when it reaches the lowest point of its path is 2.8 m/s

Step-by-step explanation:

Given;

mass of pendulum, m = 1.5 kg

height of pendulum, h = 0.4 m

At the highest point, the velocity of the pendulum is zero and the kinetic energy is zero, so the total energy at that point is potential energy;

U = mgh

At the lowest point, the height of the pendulum is zero and the potential energy is zero, so the total energy at that point is kinetic energy;

KE = ¹/₂mv²

Apply the principle of conservation of mechanical energy

KE = U

¹/₂mv² = mgh

¹/₂v² = gh

v² = 2gh

v = √2gh

v = √(2 x 9.8 x 0.4)

v = 2.8 m/s

Therefore, the speed of the pendulum when it reaches the lowest path is 2.8 m/s