Understanding the Joule: Defining and Applying Energy in Physics

[mudkip9001]

This is really basic, but I can't seem to find that one piece of reasoning that I must be missing...

I don't understand the definition of the joule; 'the energy given to a body if a force of 1N is applied for the distance of one meter'

If I apply 1N to an object of mass 1000kg until it has moved one meter, will I not have given it more energy than if I do the same to an object of 1 kg?

edit: oops, didn't mean to post it in learing materials... sorry.

 

[tiny-tim]

Hi mudkip9001!

I don't understand the definition of the joule; 'the energy given to a body if a force of 1N is applied for the distance of one meter'

If I apply 1N to an object of mass 1000kg until it has moved one meter, will I not have given it more energy than if I do the same to an object of 1 kg?

ah … interesting question …

v² = 2as, and so W = Fs = mas = mv²/2 …

they have the same energy because the heavier mass is moving much slower

 

[sir-pinski]

No need to apologize for posting in the learning materials section, it's a great place to ask questions and learn more about a topic!

To answer your question, the definition of the joule may seem confusing at first, but it is important to understand that energy is a quantity that is dependent on both force and distance. In your example, yes, you would have given more energy to the 1000kg object compared to the 1kg object, as the force is the same but the distance moved is different. This is because energy is also dependent on the mass of the object.

To understand this concept better, think of it in terms of work. Work is defined as the force applied multiplied by the distance moved in the direction of the force. So, in your example, the work done on the 1000kg object would be greater than the work done on the 1kg object, as the distance moved is greater.

In summary, the definition of the joule is based on the work done on an object by applying a force over a certain distance. The mass of the object also plays a role in determining the amount of energy given to it. I hope this helps clarify the concept for you!