Inclined plane with massless, frictionless winch

Click For Summary
SUMMARY

The discussion centers on calculating the work done on a 100 kg box being pulled up a 45° inclined plane by a massless, frictionless winch. The winch operates at a constant angular velocity of ω = 3.14 radians/sec and has a radius of 0.25 m. The correct calculation for the work done when the winch makes 10 complete revolutions results in 13620 J, factoring in gravitational potential energy and frictional forces. The formula used involves summing opposing forces and multiplying by the distance moved along the incline.

PREREQUISITES
  • Understanding of basic physics concepts such as work, energy, and forces.
  • Familiarity with inclined plane mechanics and friction coefficients.
  • Knowledge of angular motion and its relation to linear displacement.
  • Ability to apply trigonometric functions in physics problems.
NEXT STEPS
  • Study the principles of work and energy in physics.
  • Learn about inclined plane dynamics and frictional forces.
  • Explore the relationship between angular velocity and linear distance.
  • Practice problems involving massless pulleys and winches in physics.
USEFUL FOR

Students of physics, engineers working with mechanical systems, and anyone interested in understanding the dynamics of inclined planes and winches.

r34racer01
Messages
62
Reaction score
0
phys.jpg


A 100 kg box is pulled up an inclined plane by a massless, frictionless winch to which it is attached by a massless rope. The plane makes an angle of 45° with respect to the horizontal. The coefficient of friction between the box and the plane is μ = 0.25 (with μs = μk). The winch has a radius of 0.25 m and is turned at a constant angular velocity of ω = 3.14 radians/sec.

How much work is done on the 100 kg box by the rope when the winch makes 10 complete revolutions?

(a) 4380 J
(b) 5235 J
(c) 9262 J
(d) 12531 J
(e) 13620 J


So I did d = [2(.25)(3.34)]10 since we need 10 rev. And then...
W = mgh + uNd
W = mg(d sin 45) + u(mg cos 45)d
but I'm not getting the right answer, I think I'm suppose to get 13620J, but how do I get that?



 
Physics news on Phys.org
I'm not so sure that W = mgh + uNd
Isn't mgh the gravitational potential that is gained by doing the work?

I would sum up the forces that are opposing the pull of the rope (parallel to the plane) and multiply it by the distance it moves
 

Similar threads

Replies
19
Views
3K
  • · Replies 7 ·
Replies
7
Views
3K
Replies
14
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
Replies
1
Views
2K
Replies
6
Views
5K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
4K
Replies
22
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K