How to Calculate Work at a 30 Degree Angle on a Ski Slope?

  • Thread starter Thread starter bearhug
  • Start date Start date
  • Tags Tags
    Angle Work
Click For Summary

Homework Help Overview

The problem involves calculating the work required to pull a skier up a slope at a specific angle and speed. The subject area includes concepts from mechanics, specifically work, force, and vector resolution in the context of inclined planes.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the need to apply force equations and vector components to determine the work done. Some suggest using basic work formulas while others express confusion about the role of vectors in the problem.

Discussion Status

The discussion is ongoing, with participants offering different perspectives on how to approach the problem. Some guidance has been provided regarding the use of basic equations, but there remains uncertainty about the application of vectors and the resolution of forces.

Contextual Notes

Participants note a lack of clarity in the textbook regarding vector application, which may be contributing to confusion in solving the problem. There is also mention of assumptions related to constant speed and net force.

bearhug
Messages
78
Reaction score
0
A skier of mass 71 kg is pulled up a slope by a motor-driven cable.
(a) How much work is required to pull him a distance of 55 m up a 30° slope at a constant speed of 1.1 m/s

My whole problem with this question is that I'm not sure if I need to include ∑Fx and ∑Fy (where ∑Fx = mgsinӨ=ma and ∑Fy= n-mgcosӨ) in order to find F. This is where I'm getting stuck to solve for W
W=FcosӨ Δr
I just need help in getting started with this problem because I keep getting stuck. Any help would be greatly appreciated.
 
Physics news on Phys.org
I think you can just use the simple [tex]W = F \times d[/tex] equation for this problem. The total distance can be calculated using trigonometry.
You know that [tex]F = m \times a \ \Longrightarrow \ F = m \times \frac{d}{t^2}[/tex].
And you can also calculate the total time it takes to move the object to the final destination since you know the distance and the velocity of it. I think this would work.
 
Last edited:
W = mg = 71 kg * 9.8 m/s2.

However, the Weight points directly down with gravity. Weight (force) is a vector, and it can be resolved into two components, one normal to the slope surface, and one parallel, pointing down hill. The cable would be pulling up hill at constant speed. Constant speed means not acceleration so no net force.
 
I'm still confused as to what you are describing. Plus I figured vectors were involved however my book doesn't really explain how to use vectors in relation to this sort of problem. Could you explain a little more any help is appreciated.
 

Similar threads

  • · Replies 9 ·
Replies
9
Views
2K
Replies
3
Views
2K
Replies
1
Views
2K
  • · Replies 15 ·
Replies
15
Views
3K
Replies
13
Views
7K
Replies
7
Views
7K
Replies
1
Views
2K
Replies
3
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K