Work and energy without friction

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Homework Help Overview

The discussion revolves around a physics problem involving work and energy on a frictionless inclined plane. A student is tasked with determining the distance a block travels along the incline after a certain amount of work is done on it.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants explore the relationship between work done and the distance traveled along the incline, questioning the need for force in the calculations. Some suggest using conservation of energy principles, while others focus on deriving height from the work-energy equation.

Discussion Status

Participants are actively discussing different approaches to solve the problem, including the use of trigonometry to relate height and distance along the incline. There is an ongoing exchange about the correctness of calculations and the equations being used, with some guidance provided on the steps to take.

Contextual Notes

There appears to be confusion regarding the application of equations and the interpretation of results, with participants questioning their calculations and the assumptions made in the problem setup.

catmd13
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Homework Statement


A physics student shoves a 0.50-kg block from the bottom of a frictionless 30.0° inclined plane. The student performs 4.0 J of work and the block slides a distance s along the incline before it stops. Determine the value of s in cm.


Homework Equations



W=(Fcostheta)s

The Attempt at a Solution


In the problem we have the weight of the block the degree of the incline and the work done. i was wondering how I would find F cause wouldn't W=4.0J cos=30.0.
 
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The energy only depends on the vertical distance traveled.
Find that from W=mgh and then simple trig gives you the distance along the slope
 
Don't worry about trying to figure out the force that the student exerted (assuming that's what you mean by F). You don't have enough information and it's not needed anyway.

Hint: Use conservation of energy.
 
I did W=mgh
4.0J=(0.50kg)(9.80)h

Im still getting the wrong answer am i using the wrong equation or an error in my math
 
catmd13 said:
I did W=mgh
4.0J=(0.50kg)(9.80)h

Im still getting the wrong answer am i using the wrong equation or an error in my math
That equation will give you the height, which is the first step. Now use a bit of trig (as mgb_phys said) to find the distance along the incline that corresponds to that height.
 
i get 180 cm is this correct
 
catmd13 said:
i get 180 cm is this correct
No. Show the steps you used to get that result.
 

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