## Kinetic energy

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Madeline Lequang 1G
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Joined: Fri Sep 28, 2018 12:27 am

### Kinetic energy

Does the formula (1/2)mv^2 only apply to kinetic energy? or can it be used for other types of energy?

Josephine Chan 1B
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Joined: Fri Sep 28, 2018 12:17 am

### Re: Kinetic energy

That formula is specifically for kinetic energy so don't think it can be used for other types of energy.

Brian Kwak 1D
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Joined: Fri Sep 28, 2018 12:17 am

### Re: Kinetic energy

As stated before the Formula is used only to find the Kinetic energy but if you don’t have all the requested information I’m pretty sure you can also use de Broglie equation to help you find that portion. Since the equation is KE= 1/2 MV^2 and you don’t have velocity you can use de Broglie’s equation to help you find that information if they give you lets say the mass and wave length. I hope this helps a bit.

305115396
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Joined: Fri Sep 28, 2018 12:16 am

### Re: Kinetic energy

It is only used for kinetic energy. It is specifically given as the equation for kinetic energy on the equations sheet so there is no reason to think that it is used for other types of energy

Karan Thaker 2L
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Joined: Fri Sep 28, 2018 12:26 am

### Re: Kinetic energy

I agree. In our context it is frequently used in electron kinetic energy calculations and for relating debroglie principles to the photo electric effect.

Aiden Atoori 1C
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Joined: Fri Sep 28, 2018 12:24 am

### Re: Kinetic energy

We use it to only find kinetic energy!

Jack Hewitt 2H
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### Re: Kinetic energy

Madeline Lequang 1G wrote:Does the formula (1/2)mv^2 only apply to kinetic energy? or can it be used for other types of energy?

It only applies to kinetic energy.

Grace Diaz 3F
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Joined: Fri Sep 28, 2018 12:24 am

### Re: Kinetic energy

It only applies to kinetic energy. For example the energy of a photon is measured by plank's constant times it's frequency.

805169754
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Joined: Fri Sep 28, 2018 12:19 am

### Re: Kinetic energy

The formula only works for kinetic energy because kinetic energy is the only energy that is directly proportional to the mass of the object and to the square of its velocity

Jeril Joseph 1B
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### Re: Kinetic energy

Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 105 m.s-1. The work function for sodium is 150.6 kJ.mol-1.

What is the kinetic energy of the ejected electron?
A. 3.01 x 1025 J

B. 3.98 x 10-19 J

C. 7.96 x 10-19 J

D. 1.99 x 10-19 J

E. None of the above

How would you go about solving this problem? I know you would use the Ek=1/2mv^2 formula, but I don't know what the mass would be. Someone please help.

Jeril Joseph 1B
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### Re: Kinetic energy

Nevermind, I figured it out. It's the mass of the electron, right?

205458163
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Joined: Wed Jun 26, 2019 12:15 am

### Re: Kinetic energy

In my opinion, this formula is only for the kinetic energy, or sometimes the electron doesn't have kinetic energy.

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