# The Naked Scientists Forum

### Author Topic: What causes relativistic mass increase?  (Read 538 times)

#### jeffreyH

• Global Moderator
• Neilep Level Member
• Posts: 3774
• Thanked: 47 times
• The graviton sucks
##### What causes relativistic mass increase?
« on: 27/05/2016 22:57:03 »
What causes relativistic mass increase?

This is an intriguing question.

I am looking for ideas on the cause.
« Last Edit: 28/05/2016 08:34:21 by chris »

#### Flatland

• First timers
• Posts: 5
##### Re: What causes relativistic mass increase?
« Reply #1 on: 28/05/2016 00:10:57 »
The keyword here is "relativistic."  Due to the speed of light limit, a stationary observer will see that more and more energy will be required as you accelerate closer to the speed of light.  Since mass can be defined as the resistance to acceleration, this stationary observer will come to the conclusion that your mass has increase.

#### jeffreyH

• Global Moderator
• Neilep Level Member
• Posts: 3774
• Thanked: 47 times
• The graviton sucks
##### Re: What causes relativistic mass increase?
« Reply #2 on: 28/05/2016 01:41:34 »
Ok so I'll frame it differently. What causes the resistance to an increase in velocity?

#### PmbPhy

• Neilep Level Member
• Posts: 2760
• Thanked: 38 times
##### Re: What causes relativistic mass increase?
« Reply #3 on: 28/05/2016 05:42:52 »
Quote from: jeffreyH
This is an intriguing question. I am looking for ideas on the cause.
Hi Jeff!

I don't believe that you really wanted to ask What causes relativistic mass increase? because the correct and precise answer is An increase in speed.

Please correct me if I'm wrong but I believe that what you're really seeking to understand is the explanation of the increase in mass due to an increase in speed. Is that correct? If so then the answer is simple: with an increase in speed comes an increase in time dilation and a decrease in length. The best way to understand all of this is to follow the derivation which shows the relationship between mass and speed. You can find if on my website at: http://www.newenglandphysics.org/physics_world/sr/inertial_mass.htm

There is an error in there somewhere which I've yet to correct. But if you follow it carefully then you'll find it. It's merely a typographical error.

The following users thanked this post: jeffreyH

#### Thebox

• Neilep Level Member
• Posts: 3139
• Thanked: 42 times
##### Re: What causes relativistic mass increase?
« Reply #4 on: 28/05/2016 08:29:46 »
The keyword here is "relativistic."  Due to the speed of light limit, a stationary observer will see that more and more energy will be required as you accelerate closer to the speed of light.  Since mass can be defined as the resistance to acceleration, this stationary observer will come to the conclusion that your mass has increase.

Hmm, no, inertia is the resistance to acceleration.

#### Thebox

• Neilep Level Member
• Posts: 3139
• Thanked: 42 times
##### Re: What causes relativistic mass increase?
« Reply #5 on: 28/05/2016 08:32:32 »
Quote from: jeffreyH
This is an intriguing question. I am looking for ideas on the cause.
Hi Jeff!

I don't believe that you really wanted to ask What causes relativistic mass increase? because the correct and precise answer is An increase in speed.

Please correct me if I'm wrong but I believe that what you're really seeking to understand is the explanation of the increase in mass due to an increase in speed. Is that correct? If so then the answer is simple: with an increase in speed comes an increase in time dilation and a decrease in length. The best way to understand all of this is to follow the derivation which shows the relationship between mass and speed. You can find if on my website at: http://www.newenglandphysics.org/physics_world/sr/inertial_mass.htm

There is an error in there somewhere which I've yet to correct. But if you follow it carefully then you'll find it. It's merely a typographical error.

Hi Pmb, no an increase in speed is not a change in relativistic ''mass'', the ''mass'' does not change ever, an increase in speed increases the potential force , >relativistic ''mass''=>F

#### Thebox

• Neilep Level Member
• Posts: 3139
• Thanked: 42 times
##### Re: What causes relativistic mass increase?
« Reply #6 on: 28/05/2016 08:36:12 »
Ok so I'll frame it differently. What causes the resistance to an increase in velocity?

Linear ''inertia'' (gravitational drag)

I=    where g is gravity and V is velocity and I is inertia

#### jeffreyH

• Global Moderator
• Neilep Level Member
• Posts: 3774
• Thanked: 47 times
• The graviton sucks
##### Re: What causes relativistic mass increase?
« Reply #7 on: 28/05/2016 12:28:06 »
Quote from: jeffreyH
This is an intriguing question. I am looking for ideas on the cause.
Hi Jeff!

I don't believe that you really wanted to ask What causes relativistic mass increase? because the correct and precise answer is An increase in speed.

Please correct me if I'm wrong but I believe that what you're really seeking to understand is the explanation of the increase in mass due to an increase in speed. Is that correct? If so then the answer is simple: with an increase in speed comes an increase in time dilation and a decrease in length. The best way to understand all of this is to follow the derivation which shows the relationship between mass and speed. You can find if on my website at: http://www.newenglandphysics.org/physics_world/sr/inertial_mass.htm

There is an error in there somewhere which I've yet to correct. But if you follow it carefully then you'll find it. It's merely a typographical error.

Hi Pete it's good to review your page again now since I know more than I did. I thought you might answer this one. I am still thinking about this question. Yes all you say is correct but I am looking for some other connection. This may be folly on my part. I don't know yet. Thanks for the answer it is good to review things so that you don't get things muddled.

#### The Naked Scientists Forum

##### Re: What causes relativistic mass increase?
« Reply #7 on: 28/05/2016 12:28:06 »