Diameter of the football players' piston?

  • Thread starter Thread starter benedict9999
  • Start date Start date
  • Tags Tags
    Diameter Piston
AI Thread Summary
The discussion centers on calculating the diameter of a piston used to lift four football players with a hydraulic lift. The initial calculation attempted to relate the weight of the cheerleader and the players through their respective piston diameters. Participants noted potential calculation errors and discussed the importance of cross-multiplication and significant figures. After reevaluation, the correct diameter for the football players' piston was confirmed to be approximately 55.86 cm. The thread highlights the importance of careful calculations in physics problems.
benedict9999
Messages
4
Reaction score
0

Homework Statement


A 54.0 kg cheerleader uses an oil-filled hydraulic lift to hold four 130 kg football players at a height of 1.40 m. If her piston is 18.0 cm in diameter, what is the diameter of the football players' piston?


Homework Equations





The Attempt at a Solution



54 /18^2 = 520/x^2
x= 55.85696 cm

What am i doing wrong?
 
Physics news on Phys.org
Run that through your calculator again; looks like a calculation error.
Might be worth writing out the cross multiplication step.
 
it's not... I still get the same answer running it through my calculator
 
Why do you think it is wrong?

Sig figs perhaps?

Edit: I must admit thread subject made me wonder if it is not XXX site link spam...
 
Last edited:
Sorry, I made the mistake! Checked it again and got your answer.
 
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