How Fast Should a Space Station Rotate to Mimic Earth's Gravity?

AI Thread Summary
To mimic Earth's gravity in a proposed space station with a 62.0 m diameter, the correct angular speed must be calculated. The initial calculations incorrectly used the diameter as the radius, leading to an incorrect angular speed of 0.398 rad/s. Upon realizing the mistake, the correct radius of 31.0 m should be used, which will yield the accurate angular speed. Using the correct values, the physics is sound, and the calculations can be adjusted accordingly. This highlights the importance of carefully reading problem statements in physics.
Becca93
Messages
84
Reaction score
1
Homework Statement
A proposed space station includes living quarters in a circular ring 62.0 m in diameter. At what angular speed should the ring rotate so the occupants feel that they have the same weight as they do on Earth?


The attempt at a solution

I assumed that to do this problem, Fcp had to equal the force of gravity.

Fcp = Fg

mv^2 / r = mg
v^2 / r = g
v = √(rg)
v = √(62g)
v = 24.65

v = ωr
ω = v/r
ω = 24.65 / 62
ω = 0.398 rad/s

This isn't correct.

Does anyone have any advice on what to do differently? Any help would be greatly appreciated.
 
Physics news on Phys.org
Becca93 said:
Homework Statement
A proposed space station includes living quarters in a circular ring 62.0 m in diameter. At what angular speed should the ring rotate so the occupants feel that they have the same weight as they do on Earth?


The attempt at a solution

I assumed that to do this problem, Fcp had to equal the force of gravity.

Fcp = Fg

mv^2 / r = mg
v^2 / r = g
v = √(rg)
v = √(62g)
v = 24.65

v = ωr
ω = v/r
ω = 24.65 / 62
ω = 0.398 rad/s

This isn't correct.

Does anyone have any advice on what to do differently? Any help would be greatly appreciated.

I don't see anything wrong with your physics. The problem may lie with your math. What value of g did you use? Using g = 9.81 N/kg, I get v = 24.66 m/s (to two decimal places).
 
cepheid said:
I don't see anything wrong with your physics. The problem may lie with your math. What value of g did you use? Using g = 9.81 N/kg, I get v = 24.66 m/s (to two decimal places).

I tried both, but when whittled down to the required three sigfigs, the answer is still 0.398 rad/s.

I'm at a loss as to what to do differently.
 
Becca93 said:
I tried both, but when whittled down to the required three sigfigs, the answer is still 0.398 rad/s.

I'm at a loss as to what to do differently.

Oh. :redface:

62.0 m is the diameter of the space station, not its radius.

It helps if you read the problem carefully (and I apply this advice to you and me both!).
 
cepheid said:
Oh. :redface:

62.0 m is the diameter of the space station, not its radius.

It helps if you read the problem carefully (and I apply this advice to you and me both!).

:redface: Do you ever have one of those moments where you just can't believe you mixed up something really simple?

Thank you very much for pointing that out. I feel a bit foolish, but I do have the right answer now.
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Back
Top