# What is the best method for electromagnetic propulsion?

I mean by the best the one that use the least energy to produce the grater force capable of carrying weights .

Say you have a pulley attached to a ceiling with height of 3 meters, around the pulley is a string that attached to a 30 kg weight and on the other side of the string you want to use electromagnetic propulsion to lift the weight up ...... What method will you use and how much power will it use ?

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## Answers and Replies

sophiecentaur
Science Advisor
Gold Member
2020 Award
You would need to specify what sort of forces and weights are involved. Things like this don't easily scale for different sizes - take a slot racing car and a F1 style electric car. An electromagnetic engine that's suitable for one purpose may be hopeless for another purpose.

berkeman
Mentor
I mean by the best the one that use the least energy to produce the grater force capable of carrying weights .
As long as you can run tracks where you want to go...

https://en.wikipedia.org/wiki/Maglev

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anorlunda
Staff Emeritus
We need more detail to answer.

To propel a space probe, an ion thruster is used.

To propel a race car, an electric motor is used.

To propel protons in an accelerator, magnets are used.

Edit: Are you working on a SF story?

russ_watters
We need more detail to answer.

To propel a space probe, an ion thruster is used.

To propel a race car, an electric motor is used.

To propel protons in an accelerator, magnets are used.

Edit: Are you working on a SF story?

OK.... I wasn't clear at all

Say you have a pulley attached to a ceiling with height of 3 meters, around the pulley is a string that attached to a 30 kg weight and on the other side of the string you want to use electromagnetic propulsion to lift the weight up ...... What method will you use and how much power will it use ?

phyzguy
Science Advisor
How about winding the string around the shaft of an electric motor? Does an electric motor qualify as "electromagnetic propulsion"?

russ_watters and Dale
Dale
Mentor
2020 Award
Say you have a pulley attached to a ceiling with height of 3 meters, around the pulley is a string that attached to a 30 kg weight and on the other side of the string you want to use electromagnetic propulsion to lift the weight up ...... What method will you use and how much power will it use ?
I would use an electric motor. Power requirements depend on how fast you want it raised. The formula is P=mgh/t and you will want to make it larger to account for friction in the pulley

Edit: beat by @phyzguy !

anorlunda
Staff Emeritus
An ordinary electric motor is the best option.

It will take 3*30 kg*m or 883 n*m or 883 joules of energy to lift neglecting friction.

Can you do the rest? Do you know what a joule is? a watt?

An ordinary electric motor is the best option.

It will take 3*30 kg*m or 883 n*m or 883 joules of energy to lift neglecting friction.

Can you do the rest? Do you know what a joule is? a watt?
That will do it ..... Thanks

berkeman