Elementary Physics - Energy Related Problem

In summary, a 0.125 kg wrench was dropped from the roof of a building under construction and was seen by a worker on the 8th floor. The wrench was traveling at a speed of 33.1 m/s at that level. The first floor of the building is 12.0m high and each successive floor is 8.00m high. Neglecting air friction, the number of floors in the building can be calculated by finding the difference in potential energy between the roof and the 8th floor and dividing it by the potential energy of one floor. The speed of the wrench just before it hit the ground can be determined using the equation for kinetic energy. Its kinetic energy just before impact can also be
  • #1
Valedictorian
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Homework Statement


A worker on the roof of a building that is under construction dropped a 0.125 kg wrench over the edge. another workman on the 8th floor saw the wrench go by and determined that its speed at that level was 33.1 m/s. the first floor of the building is 12.0m high and each successive floor is 8.00m high. Neglecting air friction, how many floors does the building have? How fast was the wrench falling just before it hit the ground? What was its kinetic energy just before it hit the ground?



Homework Equations


PE=mgh
m-mass, g=9.8, h-height
KE=1/2 X mv^2
Ek-kinetic energy
PE = Potential Energy
KE = Kinetic Energy

The Attempt at a Solution


I don't really have any idea on how to solve this...it was a prize question by my teacher. Thanks in advance for any help!
 
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  • #2
First thing to do is to determine how much higher the top of the roof is than the 8th floor where the other workman somehow determined the speed of the wrench.

Hint: How does potential energy relate to kinetic energy in this problem?
 
  • #3
Nevermind, I just thought the problem was more intimidating than it really was. Thank you for your help though! :biggrin:
 

FAQ: Elementary Physics - Energy Related Problem

1. What is energy?

Energy is defined as the ability to do work or cause change. It comes in many forms such as mechanical, thermal, electromagnetic, and chemical energy.

2. What is the law of conservation of energy?

The law of conservation of energy states that energy cannot be created or destroyed, but it can be transferred or transformed from one form to another.

3. How is energy related to matter?

Einstein's famous equation, E=mc², shows the relationship between energy and matter. It states that energy and matter are interchangeable and can be converted into one another.

4. What is the difference between potential and kinetic energy?

Potential energy is the energy an object has due to its position or state, while kinetic energy is the energy an object has due to its motion. Potential energy can be converted into kinetic energy and vice versa.

5. How can energy be conserved?

Energy can be conserved by using renewable energy sources, reducing energy consumption, and improving energy efficiency. It is also important to recycle and properly dispose of waste to conserve energy resources.

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