(CHALLENGING )Trigonometry / geometry proof

AI Thread Summary
The discussion revolves around proving that the length GL equals R(THETA) in a circular structure. A participant suggests that for a circle of radius R, the length of a circular segment corresponding to an angle theta is R theta, which is based on the definition of radians. They explain that if G' is a point on the cylinder, then the arc length G'T also measures R theta. The conversation seeks additional proofs or insights to support this conclusion. Overall, the thread emphasizes the geometric relationship between angles and arc lengths in circular structures.
Doctor_Doom
Messages
14
Reaction score
0
(CHALLENGING!)Trigonometry / geometry proof

Hey guys I've spent a couple hours on this without even coming close. I'm hoping someone here can drop me a hint.

From the above image I need to proof that GL is R(THETA) in length.
The only other information I have is that GT extended is a type of sheet (metal sheet) balancing and "rocking" forward and backward on the circular structure of radius R (cylinder).

Hints or help or links would be of HUGE assistance.

Thanks in advance!
 
Last edited:
Physics news on Phys.org


Is there anything to prove?
If you have a circle of radius R, then a circular segment with angle theta has length R theta.
That's about the definition of radians (a unit circle goes around 2pi radians, and has circumference 2pi).

If you let G' be the marked point on the cylinder below G (near which the label for c is written), then G'T along the circle has length R theta. Since G is a point on the circle with center T which also goes through G' (as indicated by the circular arc), GT is also R theta.
 


Thanks that makes sense. Anyone else have a proof for what was stated above?
 
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...

Similar threads

2
Replies
77
Views
15K
Replies
43
Views
12K
4
Replies
175
Views
25K
Replies
39
Views
14K
Replies
2
Views
9K
Replies
1
Views
3K
Back
Top