Pendulum

Two children are at the playground. The swings squeak as the youngsters travel back and forth. What do we know about the children and about the swings if they are squeaking in unison (at the same time)?

• They weigh the same amount

• The swing length must be the same

• They were released at the same angle

• They are twins

Identical twins Slow Joe and Flyin’ Brian spot a rope dangling from a sturdy tree limb over Lake Decatur. Slow Joe trots toward the rope at his usual slow pace, jumps from dry ground, and grabs the rope in mid-air, swinging back and forth. Later Flyin’ Brian wants to have fun, too, so he races at this usual sprinting speed toward the rope, jumps from dry ground, and grabs the rope in the same place as Slow Joe had. How do the pendulum motions of the two boys compare?

• Joe swings back and forth faster

• Brian swings back and forth faster

• They swing back and forth at the same time

• Brian is going to wipe out

Mary builds her very own grandfather clock. She notices that the clock pendulum swings to one side and back in 0.70 seconds. What can she do to adjust the pendulum to make to period exactly 1.0 seconds?

• Get a heavier weight to use inside the clock

• Make the length of the pendulum longer

• Make the length of the pendulum shorter

• Try to sell it on ebay

A gust of wind crosses the family porch. A set of wind chimes swings back and forth in less time than the hanging bird feeder next to it. Explain the cause(s) of this difference in the period.

• The wind must be hitting them differently

• The wind chimes are heavier than the bird feeder

• The bird feeder is heavier than the wind chimes

• The bird feeder has a shorter length of string

• The bird feeder has a longer length of string

An anchor hangs by a chain over the bow of a ship, gently swaying above the tiny waves of the harbor. A storm blows in and the waves grow larger. What will happen to the pendulum motion of the anchor?

• Nothing

• It speeds up

• It slows down

• It snaps

An anchor hangs by a chain over the bow of a ship, gently swaying above the tiny waves of the harbor. A storm blows in and the waves grow larger. What will happen to the pendulum motion of the anchor? A panicked sailor on the ship in climbs down the chain and stands on the anchor during the storm. What happens to the pendulum motion of the anchor?

• Nothing

• It speeds up

• It slows down

When we're talking about a pendulum, what does T stand for?

• pi

• period

• length

• gravity

What is the unit for the period of a pendulum?

• second

• meter

• m/s/s

• Newton

As a pendulum gets longer, what happens to the period?

• doesn't change

• decreases

• increases

Which would have the longest period?

Pendulum A: A 200-g mass attached to a 1.0-m length string

Pendulum B: A 400-g mass attached to a 0.5-m length string

• A

• B

• Same