Question

A pendulum of mass 22 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 13 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)
10 m
B
OA. 134 J
OB. 45 J
OC. 218 J
D. 297 J

Answer 1

Lost energy:

D. 297 J

Step-by-step explanation:

Giver:

m =22 kg

h = 10 m

V = 13 m/s

_________________

ΔE - ?

1)

Potential energy:

Ep = m·g·h = 22·9.8·10 = 2 156 J

2)

Kinetic energy:

Ek = m·V² / 2 = 22·13² / 2 = 1 859 J

3)

Lost energy:

ΔE = Ep - Ek = 2 156 - 1 859 = 297 J

4)

Correct answer:

D. 297 J