# Amusement park ride gravitation problem

#### holmeskaei

1. Homework Statement

In an old-fashioned amusement park ride, passengers stand inside a 5.4-m-diameter hollow steel cylinder with their backs against the wall. The cylinder begins to rotate about a vertical axis. Then the floor on which the passengers are standing suddenly drops away! If all goes well, the passengers will "stick" to the wall and not slide. Clothing has a static coefficient of friction against steel in the range 0.64 to 1.0 and a kinetic coefficient in the range 0.40 to 0.70. A sign next to the entrance says "No children under 30 kg allowed."

2. Homework Equations
f(fric)=(us)(n)
Fr=n=mv^2/r
Fz=f=mg
Ft=0
w=v/r

3. The Attempt at a Solution
f=(0.64)(9.8*30)=188.16N
188.16N=(30)(v)^2/2.7, v=4.1151m/s
This answer is not correct, however. Any guidance is appreciated. I don't want the answer, just what I am doing incorrectly.

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#### PhanthomJay

Homework Helper
Gold Member
Re: Gravitron

1. Homework Statement

In an old-fashioned amusement park ride, passengers stand inside a 5.4-m-diameter hollow steel cylinder with their backs against the wall. The cylinder begins to rotate about a vertical axis. Then the floor on which the passengers are standing suddenly drops away! If all goes well, the passengers will "stick" to the wall and not slide. Clothing has a static coefficient of friction against steel in the range 0.64 to 1.0 and a kinetic coefficient in the range 0.40 to 0.70. A sign next to the entrance says "No children under 30 kg allowed."

2. Homework Equations
f(fric)=(us)(n)
Fr=n=mv^2/r
Fz=f=mg
Ft=0
w=v/r

3. The Attempt at a Solution
f=(0.64)(9.8*30)=188.16N use your 3rd relevant equation, f(fric)= mg. You are incorrectly assuming that the Normal force is the person's weight.
188.16N=(30)(v)^2/2.7, v=4.1151m/s
This answer is not correct, however. Any guidance is appreciated. I don't want the answer, just what I am doing incorrectly.

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