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tem_osu

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**[SOLVED] Vertical Circular Motion & Centripetal Acceleration**

## Homework Statement

1) A car travels at a constant speed around a circular track whose radius is 2.1 km. The car goes once around the track in 410 s. What is the magnitude of the centripetal acceleration of the car?

## Homework Equations

a=(v^2)/r

## The Attempt at a Solution

a=((2100/410)^2)/2100=0.01249 - wrong answer

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## Homework Statement

2)A roller coaster at an amusement park has a dip that bottoms out in a vertical circle of radius r. A passenger feels the seat of the car pushing upward on her with a force equal to five times her weight as she goes through the dip. If r = 20.5 m, how fast is the roller coaster traveling at the bottom of the dip?

## Homework Equations

F-mg = m(v^2/r)

## The Attempt at a Solution

v^2 = (20.5)(9.8)

v = 14.17 m/s - wrong answer

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Please help me, I don't know what I'm doing wrong.