How Fast Must a Student Climb to Match a Lightbulb's Power Output?

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Homework Help Overview

The problem involves a student climbing a rope and seeks to determine the average speed required to match the power output of a lightbulb. The context includes concepts from physics such as potential energy, kinetic energy, and power.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the potential energy calculation and its implications for the work done by the student. Questions arise about how to relate this work to the power output of the lightbulb and how to find the time required for the climb.

Discussion Status

Some participants have provided hints regarding the relationship between power, work, and time, suggesting that finding the time is a crucial next step. Multiple interpretations of how to approach the problem are being explored, particularly concerning the equations of motion and the definition of power.

Contextual Notes

There is uncertainty about the appropriate equations to use for finding time and how to apply the concept of power in this context. The original poster expresses confusion about the next steps in the problem-solving process.

Knfoster
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Homework Statement


A 54.2 kg student climbs a 6.95 m rope and stops at the top. What must her average speede in order to match the power output of a 110 W lightbulb?

Homework Equations


PE=mgh
KE=1/2mv^2
W=(Xf-Xi)(cos theta)(F)
W= delta KE
PE+KE = PE+KE (before and after)

The Attempt at a Solution


I know that the PE for the student is 3691.6 J at the top of the rope. And KE is zero at the top of the rope, so PE at the bottom of the rope would be 0, and KE would be 3691.6.

I don't know what to do next and I don't know how to use the 110 W light bulb.

Please help. Thank you.
 
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Knfoster said:
I know that the PE for the student is 3691.6 J at the top of the rope.
Good. This represents the work she must do to raise herself up the rope. Hint: How quickly must she climb the rope so that her power equals 110 W? (Find the time, then figure out her speed.)
 
How do I go about finding the time? Is there a certain equation that I need?
 
Do I use one of the four equations for motion?
 
Knfoster said:
How do I go about finding the time? Is there a certain equation that I need?
What's the definition of power?
 

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