How Does Force Direction Affect Work Done?

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Homework Help Overview

The discussion revolves around the concept of work done by forces, specifically examining how the direction of force affects the work done on an object. The context includes two problems: one involving a crate being dragged across a floor and another involving two ice skaters pushing off from each other.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • Participants are attempting to calculate the work done by both horizontal and vertical components of a force acting on a crate. Questions are raised about the work done by the vertical component and the total work done. In the second problem, participants are exploring the conservation of momentum and the resulting speeds of the skaters after they push off.

Discussion Status

Some participants have offered insights regarding the work done by the vertical force, suggesting it does no work, while others are encouraged to share their attempts at solving the second problem. There is an ongoing exploration of the momentum of the system and the corresponding speeds of the skaters, with no explicit consensus reached yet.

Contextual Notes

Participants are grappling with the implications of force direction on work and momentum, with some expressing uncertainty about their calculations and assumptions. The problems are framed within the constraints of a homework assignment, which may limit the information available for discussion.

Tdollarhyde
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A force of F = 35 N is used to drag a crate 7 m across a floor. The force is directed at an angle upward from the crate so that the vertical component of the force is Fv = 21 N and the horizontal component is Fh = 28 N as shown in the diagram.

(a) What is the work done by the horizontal component of the force?
196 Joules
(b) What is the work done by the vertical component of the force?
? Joules
(c) What is the total work done by the 35 N force?
? Joules

Can't figure out how to do the last 2 for the life of my. You don't even have to do it for me, I'll be good with just an equation.

Also, Here is another one I can't figure out:

An ice skater with a mass of 89 kg pushes off against a second skater with a mass of 30 kg. Both skaters are initially at rest.
(a) What is the total momentum of the system after they push off?
? kg·m/s
(b) If the larger skater moves off with a speed of 1.8 m/s, what is the corresponding speed of the smaller skater?
? m/s
 
Last edited:
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Wow, I'm stupid. The vert. force is doing 0 work, and the overall work is the same as the horizontal work!
 
Not stupid, just an oversight. Try the 2nd question and show an attempt if you still need help with that one.
 
PhanthomJay said:
Not stupid, just an oversight. Try the 2nd question and show an attempt if you still need help with that one.

Well, the total momentum is 0, and the second skater was going somewhere around 5 something. Have since put it away.
 

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