How Does Changing the Reference Point Affect the Potential Energy Calculation?

In summary, the conversation discusses calculating the change in gravitational potential energy of a trophy-Earth system as it falls from a height of 0.5m, with the option of using different origins for the coordinate system. The potential energy equation of mgy is used, and the change in potential energy is found to be approximately 9 J. It is also mentioned that there are other types of potential energy, such as electric and magnetic.
  • #1
Alaa Mahmoud
7
0

Homework Statement



a trophy being shown off by a careless athlete slips from the athlete's hands and drops on his toe.Choosing floor level as the y=0 point of your coordinate system,estimate the change in gravitational potential energy of the trophy-Earth system as the trophy falls.Repeat the calculation,using the top of the athlete's head as the origin of the coordinate.
The trophy has a mass of 2 kg,and the top of a person's toe is about 0.03m above the floor.Also the trophy falls from a height of 0.5m.

Homework Equations



(? U)=(U final)-(U inetial)

The Attempt at a Solution


I'm not sure how to get started as I'm not good in solving equations of energ.
I don't know how can I differentiate between potential energy & kinetic energy ??
 
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  • #2
Alaa Mahmoud said:

Homework Statement



a trophy being shown off by a careless athlete slips from the athlete's hands and drops on his toe.Choosing floor level as the y=0 point of your coordinate system,estimate the change in gravitational potential energy of the trophy-Earth system as the trophy falls.Repeat the calculation,using the top of the athlete's head as the origin of the coordinate.
The trophy has a mass of 2 kg,and the top of a person's toe is about 0.03m above the floor.Also the trophy falls from a height of 0.5m.

Do you know any eqn of potential energy of a body wrt Earth ?
 
  • #3
cupid.callin said:
Do you know any eqn of potential energy of a body wrt Earth ?

Potential energy of gravity=mgy
 
  • #4
Alaa Mahmoud said:
Potential energy of gravity=mgy

Yes. So What would be PE of system when trophy is in athlete's hands?
 
  • #5
PE=mg(y initial)=2*9.8*0.5=9.8J right??
 
  • #6
Alaa Mahmoud said:
PE=mg(y initial)=2*9.8*0.5=9.8J right??

Yes.
And similarly you can find the final PE ...
Then change will be ____ ?
 
  • #7
OK thank you
the change in PE will be approximately 9 J
But is there any PE except gravitational PE?
 
  • #8
Alaa Mahmoud said:
OK thank you
the change in PE will be approximately 9 J
But is there any PE except gravitational PE?

Yes. There are electric, magnetic etc
 
  • #9
OK thanks a lot :)
 

Related to How Does Changing the Reference Point Affect the Potential Energy Calculation?

1. What is potential energy of a system?

Potential energy of a system is the energy that is stored within a system due to its position or configuration. It is a type of energy that is not currently in use, but has the potential to be converted into other forms of energy.

2. How is potential energy of a system calculated?

The potential energy of a system is calculated by multiplying the mass of the object by the acceleration due to gravity and the height of the object above a reference point. The formula for potential energy is PE = mgh, where m is the mass, g is the acceleration due to gravity, and h is the height.

3. What are the different types of potential energy?

There are several types of potential energy, including gravitational potential energy, elastic potential energy, chemical potential energy, and nuclear potential energy. Gravitational potential energy is associated with an object's position in a gravitational field, while elastic potential energy is stored in an object when it is stretched or compressed. Chemical potential energy is stored in the bonds between atoms and molecules, and nuclear potential energy is stored in the nucleus of an atom.

4. What factors affect the potential energy of a system?

The potential energy of a system is affected by the mass of the object, the acceleration due to gravity, and the height of the object above a reference point. Additionally, the type of potential energy and any external forces acting on the system can also affect its potential energy.

5. How does potential energy relate to kinetic energy?

Potential energy and kinetic energy are both forms of energy that can be found in a system. Potential energy can be converted into kinetic energy and vice versa. As an object falls, its potential energy decreases while its kinetic energy increases. When an object is at its highest point, it has maximum potential energy and no kinetic energy. When it reaches the ground, it has maximum kinetic energy and no potential energy. This relationship between potential and kinetic energy is described by the law of conservation of energy.

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