No, that is not correct. The correct answer is F_t(y) = [m(gL - gy)]/L.

  • Thread starter Thread starter ahhgidaa
  • Start date Start date
  • Tags Tags
    Tension
AI Thread Summary
The discussion centers on calculating the tension in a uniform rope of length L and mass m, hung vertically. The incorrect formula presented was F_t(y) = [m(L-y)*g], which was challenged due to unit discrepancies. The correct formula is F_t(y) = [m(gL - gy)]/L, which accurately reflects the tension at a distance y from the bottom of the rope. The conversation highlights the importance of ensuring consistent units and understanding the physical implications of the formulas used. Ultimately, the correct expression for tension incorporates both mass distribution and gravitational effects.
ahhgidaa
Messages
11
Reaction score
0
a uniform rope of length L and mass m is hung vertically. what is the tension a distance y from the bottom?

my final anwer that i got was F_t(y)= [m(L-y)*g]

is this correct?
 
Physics news on Phys.org
No.

For one thing, the units are different on the left side of the equation vs. the right side.

How did you get your answer?

What does the answer you posted say in the case that y = L ?
 
force of tension a distance y from the bottom = m [(L-y)/L]*g
tension = mgh

mass per unit length times gravity
 
ahhgidaa said:
force of tension a distance y from the bottom = m [(L-y)/L]*g
tension = mgh

mass per unit length times gravity

yup! :smile:
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top