Question On A Problem Don't Agree With Teacher

  • Thread starter Thread starter PClark02
  • Start date Start date
  • Tags Tags
    Teacher
AI Thread Summary
The discussion centers on a physics problem comparing the force required to lift a box vertically versus sliding it up a ramp. The key contention is that without knowing the coefficient of friction for the ramp, one cannot accurately determine the force needed to slide the box. It is noted that if the ramp were frictionless, lifting the box would require twice the force compared to sliding it. The lack of information regarding friction is highlighted as a critical flaw in the problem's premise. Overall, the conclusion emphasizes that the comparison of forces is invalid without specifying the ramp's friction characteristics.
PClark02
Messages
5
Reaction score
0
Basic Physics stuff nothing too complex...

#1. A clerk lifts a box 1m vertically. He also slides the box to an equal height over a 2m ramp. How much more force does it take to lift the box vertically?
He stated that it would take something like twice as much(can't remember if this was it but doesn't really matter with my argument.) What I was arguing was the fact that we cannot tell how much force it takes to slide up the ramp due to the fact we have no coefficient of friction.

For example...
Would it take more force to lift a box or try to slide that same box over a ramp that's covered with tar or something with a very high coefficient of friction?

I put not enough info as my answer and am wondering how on Earth that cannot possibly be conceived as a correct answer...
Thanks in advance...
 
Physics news on Phys.org
You are correct that you cannot compare the forces unless the coefficient of friction is known. If the ramp is frictionless, it would take twice as much force to lift the box as it would to slide it up the ramp. The problem should have stated it was a frictionles ramp if that was intended.
 
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