The joule is equivalent to?

A1_is_the_goal

3 years ago

Joule is the unit of work or energy.

• Work = Force × Distance

But Force = mass × acceleration
• Work = mass x acceleration x distance

But Acceleration = velocity / time
• Work = mass × (velocity / time) × distance

But velocity = displacement / time
• Work = mass × (displacement / time) / time × distance

Since they are all fundamental quantities, input their units.

Joule = kg × m/s /s × m

Therefore: Joule is the same as Kg m² s-²

A1_is_the_goal

3 years ago

• Option C is the same as option A
🙏Please look into this matter as soon as possible.
Thanks a bunch.👍

RiverHeights

2 years ago

To solve this easily, you have to be good at physical dimensions.

Energy = Force * Distance (Distance has the physical dimension L)

Force = Mass * Acceleration (Mass has the physical dimension M)

Acceleration = Change in velocity/Time (Time has the physical dimension t)

Velocity = Distance/Time

Distance is L, and Time is T, so I can say, Velocity is equal to L/T. But as a physical dimension, I'd write it as [LT´¹].

Acceleration = Change in Velocity/Time

We already have velocity [LT´¹], and Time is T. So L/T *T. The physical dimension of acceleration becomes [LT´²]

Force = Mass * Acceleration.

Now mass has the dimension M. Since we already have acceleration, we can just add M to it to get the physical dimension of Force. The phyiscal dimension of force becomes [MLT´²].

Energy = Force * Distance

Distance is L, and we already have force, so we would just multiply it together. [L] + [MLT´²]. This means the physical dimension of energy is [ML²T´²]

So now what? Well, it's pretty simple. What is mass measured in? It's measured in Kg.
What is length measured in? It's measured in meters and since there is two L's, we square it.
What is time measured in? It's measured in seconds. There is two T's as well, but it's raised to the power of -2.

With that information, just replace the signs from [ML²T´²]. This would give us Kg m² s´²
This makes C the right answer.