Question

according to law of conservation of energy , swinging a pendulum comes to rest because
1.energy has been conserved
2. energy has changed forms

Answer 1

Pendulums stop swinging because the energy is not perfectly conserved. So 1.

Answer 2

thanks so much

Answer 3

Anytime :)

Answer 4

"comes to rest" ? at the top of the swing: conservation of energy potential + kinetic

after swinging a long time? loss of energy due to friction, heat energy .

"changed forms" seems to cover either alternative

Answer 5

no no! energy changes forms!

Answer 6

Energy isn't conserved within the system, this is true. There is drag and irregular tensile stress internally within the pendulum that causes some of the kinetic energy to be converted to free heat energy, but energy will always be perfectly conservative. Are you working from the perspective of the system? or of the universe?

Answer 7

The correct answer is "2", because in the nature, the energy is ever conservate. In the pendulums case, the kinects energy is transformed in heat energy, because the friction force between the pendulum and the air. Without the friction force, the kinects energy changes to potencial energy and vice versa, indefinitely.

Answer 8

I'm not sure there isn't any other info than what the question is.

Answer 9

1 and 2 say the same thing. Energy is conserved, because it has changed forms.

Answer 10

yes but the reason it comes to a stop is because #2, because the energy is no longer available to torque the pendulum around it's axis of rotation

Answer 11

ok thxs everyone

Answer 12

This is a badly worded question.

The analysis above is correct.

Energy is conserved, but is not conserved as "energy of motion" instead is is converted to another form which causes the pendulum to stop swinging.

Answer 13

this is exactly how the question is worded on the paper so this is not me short handed.

Answer 14

I understand. I'm not faulting you.

Just understanding that the wording is tricky. Both answers are technically correct, but one is more "right" in this application.

Answer 15

oh okay I gotcha thank you