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# 16 Lilla Lots

The Lilla Lots (Rockin' Tug) is the smallest "pendulum" at Liseberg. It moves along a rail with a radius of R ≈ 11.5 m, while also rotating around its axis. See a short movie from the sister ride från systerattraktionen Victoria at Kolmården.

• As you ride - can you fell that you are slightly lighter when the boat is in one of the highest points and slightly heavier at the bottom?
• As a first approximation, the boat can be viewed as a pendulum with the same length as the radius of curvature. How long time would you expect that the boat needs to come back to the same point (in the same direction) - i.e. how long is the period? (Remember that a "second pendulum", with a half-period of 1s has a length close to 1m)
• How fast does the boat move in the lowest point? (Use the radius and angle to estimate the elevation difference)
• How large is the centripetal acceleration in the lowest point?
• What forces act on a rider in the highest point? In the lowest point?

Read about using the smartphone to measure forces and angular velocities in Lilla Lots:  Acceleration and rotation in a pendulum ride, measured using an iPhone 4, Pendrill, A-M and Rohlén J (2011) Physics Education 46, 676

## Playground pendulum

Find a playground with swings. Close your eyes and focus on the forces acting on you as you swing. When do you feel heavier? When do you feel lighter?

## Other pendulum investigations

The pendula with different lengths suspended at a position corresponding to a half period. (a 1m pendulum has T≈2s)