What is the tension in a hockey puck swung in a horizontal circle?

AI Thread Summary
The discussion revolves around calculating the tension in a rope attached to a hockey puck swung in a horizontal circle. The puck has a mass of 200 g and is swung at 58.0 rpm on a frictionless surface. The initial calculation for tension used an incorrect radius of 0.31 m instead of the full rope length of 0.62 m. After clarification, it was acknowledged that the radius should equal the full length of the rope, leading to a reevaluation of the tension calculation. The conversation highlights the importance of correctly identifying the radius in circular motion problems.
Ly444999
Messages
19
Reaction score
0

Homework Statement


A hockey puck with mass 200 g is attached to a rope of length 62.0 cm and swung in a horizontal circle against the ice at a rate of 58.0 rpm. Assuming the ice is frictionless, what is the tension in the rope?

Homework Equations


FT = mω2r

The Attempt at a Solution


58rpm = 6.07 rad/s
200g = 0.2 kg
r = 0.31 m
FT= (0.2)(6.07)2(0.31)
= 2.28
Is this not how you solve for tension in circular motion?
I was given four answers which none of them match what I calculated 4.57 N, 417 N, 1.65×104 N, 1.09×103 N
 
Physics news on Phys.org
Ly444999 said:

Homework Statement


A hockey puck with mass 200 g is attached to a rope of length 62.0 cm and swung in a horizontal circle against the ice at a rate of 58.0 rpm. Assuming the ice is frictionless, what is the tension in the rope?

Homework Equations


FT = mω2r

The Attempt at a Solution


58rpm = 6.07 rad/s
200g = 0.2 kg
r = 0.31 m
FT= (0.2)(6.07)2(0.31)
= 2.28
Is this not how you solve for tension in circular motion?
I was given four answers which none of them match what I calculated 4.57 N, 417 N, 1.65×104 N, 1.09×103 N
Yes but you used r = 0.31 m when it is given that the length of the rope is 0.62 m.. So what is the value of r?
 
PhanthomJay said:
Yes but you used r = 0.31 m when it is given that the length of the rope is 0.62 m.. So what is the value of r?
Oh so the radius isn't half the length of the rope?
Edit: Ok I see why radius isn't half the length never mind and thank you for pointing that out
 
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