Pendulum swinging?

Question

A pendulum swinging to and fro. At what point in its motion is the KE of the pendulum bob at a maximum? At what point is its PE at a maximum? When its Ke half its maximum value how much PE does it have

KE=KINETIC ENERGY
PE=POTENTIAL ENERGY

Answer 1

Pe max when the bob is at the top of the swing. Velocity is zero, so Ke is zero.

Ke max at the bottom of the swing. Velocity is max, so Ke is max.

The midpoint of the swing is when Pe is becoming Ke and they are equalized. That is, of course, not accounting for loss due to air resistance, or friction at the end of the string.

Answer 2

Assuming no losses to friction or air resistance,
KE + PE = Total Energy and it stays a constant.

If you know the difference between PE and KE, then you'll know where each one is at a maximum during the pendulums swing. (Since you're even asking the question, I have to assume that you don't. But it's very important that you -learn- the difference between PE and KE, so the ball is in your court on this one.)

When the KE is half of it's peak value, the PE is also half of it's peak value.

Hope that helps ☺


Doug

Answer 3

Potential energy is caused by being at a distance from the centre of the earth, so it will be max when the pendulum is furthest from the centre of the earth.

Kinetic energy is the energy of motion, so it will be max when the pendulum is swinging fastest.

You should be able to work it out from that.

Answer 4

Heavier pendulums have extra weight, hence extra of a gravitational pull slowing down the swinging action. even as lighter pendulums swing swifter because there's a smaller gravitation pull.

Answer 5

on the downward swing