# Energy conversions in a game of billiards

#### Kaushik

Summary: When we hit the cue ball which energy is being converted into the kinetic energy of the ball?

When we hit the cue ball which energy is being converted into the kinetic energy of the ball?

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#### mfb

Mentor
This sounds like a homework question. What do you think?

What has energy before you hit the ball?

#### Kaushik

This sounds like a homework question.
I am just asking this out of curiosity
What has energy before you hit the ball?
Our body/arms and the balls potential energy?

#### mfb

Mentor
The ball doesn't change its height, no relevant potential energy involved.

Initially the energy is somewhere in you, sure, but I was more thinking about the situation directly before you hit the ball - with the moving cue.

#### Kaushik

The ball doesn't change its height, no relevant potential energy involved.

Initially the energy is somewhere in you, sure, but I was more thinking about the situation directly before you hit the ball - with the moving cue.
with the moving cue.
Does the cue have potential energy (Which then becomes kinetic energy)?

#### haruspex

Homework Helper
Gold Member
2018 Award
Does the cue have potential energy (Which then becomes kinetic energy)?
What form of potential energy are you suggesting? Elastic, gravitational, electric, spiritual ...?
What makes the cue move, in your experience?

#### Kaushik

What form of potential energy are you suggesting? Elastic, gravitational, electric, spiritual ...?
What makes the cue move, in your experience?
I was suggesting 'gravitation potential energy' as it is kept at some height from the earths surface.

After thinking about it, i feel like it does not make sense. Answer to the question 'Why do you think that it does not make sense?' is given below.

Let us consider a cue lying on the Earths surface. It has no gravitational potential energy but it is still possible to move it horizontally.

So is it the energy in our body which transforms into kinetic energy of the cue, later into kinetic energy of the ball?

#### haruspex

Homework Helper
Gold Member
2018 Award
So is it the energy in our body which transforms into kinetic energy of the cue, later into kinetic energy of the ball?
Yes.
Any thoughts on the transformations within the body?

#### Kaushik

Any thoughts on the transformations within the body?
After surfing on the internet for a while, I learned that it is the chemical energy in our body (stored in the mitochondria due to the food we eat) which transforms into mechanical energy of the muscles.
Is the above correct?
If yes, how exactly does the chemical energy get converted into mechanical energy of the muscles?

#### haruspex

Homework Helper
Gold Member
2018 Award
After surfing on the internet for a while, I learned that it is the chemical energy in our body (stored in the mitochondria due to the food we eat) which transforms into mechanical energy of the muscles.
Is the above correct?
If yes, how exactly does the chemical energy get converted into mechanical energy of the muscles?
Yes, that explanation skips a step.
The chemical energy is used to move ions around, creating an electrical gradient. This causes fibres in each muscle cell to slide past each other. See e.g. https://opentextbc.ca/biology/chapter/19-4-muscle-contraction-and-locomotion/

"Energy conversions in a game of billiards"

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