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# 2: Escalator

In an escalator, you move with constant velocity forwards/upwards (or downwards). Close your eyes and think about what forces act on you. (Hold on to the handrail if you are concerned about keeping your balance)

1. Does it feel different moving up compared to moving down?
2. Do you note any difference when you approach the end of the escalator?
... and does this feel different on the way down compared to the way up?
3. The lifthill in the Lisebergbanan has an angle 30°. Is this more or less than the escalator? (The photo to the left shows the escalator from outside)

## Measurements in an escalator

• How high (h) is a step?
• What is the distance (L) between the steps?
• How steep (θ) is the escalator? (How many degrees?)
• How many stairs leave the platform, e.g. during 30s? (Maybe use the phone to take a short video clip)
• How fast does the escalator move out from the platform?
• How fast does the escalator move up/down?

If the escalator is stationary, it is relatively easy to count the steps while walking up or down. Is there a way to count when it is moving? Consider letting a friend wave when stepping on the escalator at the other end and the count the number of steps before the friend arrives.

## Air pressure measurements

The graph shows a measurement of the change in air pressure in two long escalators connecting the main street (Storgatan) and the Helix station at Liseberg. The data were collected using the Android app Physics Toolbox Roller Coaster  from Vieyra software.

• Does the graph show the pressure change as you move up to the Helix station or down to the main street?
• Use the graph to estimate the height of the two escalators if the air density is ρ ≈ 1.25 kg/m3
• Is your estimate consistent with the number of steps?

## Illusions in the escalator (summer season)

1. The windows in the escalator moving up to the Helix station at Liseberg exhibit a few old photos (but not during the Christmas season). Sometimes it feels like the photos are mounted slightly askew. Are they really askew or are your eyes playing tricks?
• Take a small object on a string and let it hang freely and compare to the images.
• Does it matter if your are moving up or down?