Question

A pendulum of mass 12 kg is released from rest at some height, as shown by

point A in the image below. At the bottom of its arc at point B, it is traveling at
a speed of 19 m/s. What is the approximate amount of energy that has been
lost due to friction and air resistance? (Recall that: g = 9.8 m/s²)

20 m

A35
B186
C78
D112

Answer 1

B

Step-by-step explanation:

We EXPECT all of the POTENTIAL energy (mgh) to be converted to KINETIC energy ( 1/2 mv^2) ...but some of the energy is lost due to air friction..... the difference between these two is what is lost

mgh = 1/2 mv^2 = energy lost

12 * 9.8 * 20 = 1/2 * 12 * 19^2 = 186 J lost