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

In summary, to match the power output of a 110 W lightbulb, a 54.2 kg student climbing a 6.95 m rope must climb at a speed that allows her to do 110 J of work in 1 second. This means she must climb the rope in approximately 33 seconds, giving her an average speed of 0.21 m/s.
  • #1
Knfoster
45
0

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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  • #2
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.)
 
  • #3
How do I go about finding the time? Is there a certain equation that I need?
 
  • #4
Do I use one of the four equations for motion?
 
  • #5
Knfoster said:
How do I go about finding the time? Is there a certain equation that I need?
What's the definition of power?
 

1. What is conservation of energy?

Conservation of energy is a fundamental principle in physics that states energy cannot be created or destroyed, but can only be transferred or converted from one form to another.

2. Why is conservation of energy important?

Conservation of energy is important because it helps us understand and predict the behavior of physical systems. It also allows us to make more efficient use of energy resources and reduce waste.

3. How is energy conserved?

Energy is conserved through a variety of processes, such as the law of conservation of mass and energy, the law of thermodynamics, and through the conversion of energy from one form to another.

4. What are some examples of conservation of energy in everyday life?

Some examples of conservation of energy in everyday life include turning off lights when leaving a room, using energy-efficient appliances, and recycling materials to reduce the amount of energy needed to produce new products.

5. What are the implications of not conserving energy?

If energy is not conserved, it can lead to depletion of natural resources, increased pollution and greenhouse gas emissions, and higher energy costs. It can also disrupt the balance of ecosystems and have negative impacts on the environment.

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