Units of solar constant

In summary: J, so1 J = 1 kg*m^2*s^-2As for the second part of the problem, you're on the right track. Remember, the units of power are energy per unit time, so you need to find a way to express joules per second (J/s) in terms of kilograms, meters, and seconds. Hint: remember that 1 W = 1 J/s.In summary, the units W m-2 are equivalent to kg s-3. To find this equivalence, we can start by noting that 1 J = 1 kg*m^2*s^-2. Therefore, 1 W = 1 J/s = 1 kg*m^2*s^-
  • #1
Maya Erikson
2
0

Homework Statement



trying to show that the units W m-2 are equivalent to kg s-3

Homework Equations



1 W = 1 J s-1 ?


The Attempt at a Solution



energy per unit time?

p.s. I am very new to physics, a beginner in understanding the whole concept of units, any advice?
 
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  • #2
1W= 1J s^-1, yes.

Now you need to know what 1J is.
Just think about a formula to find energy, and you should get to your answer.R.
 
  • #3
1 J = 1 kg x m^-2 / s^-2

and, E = P x t
1 J = 1 W x 1 s

so, 1 kg x m^-2 / s^-2 = 1 kg x m^-2 / s^-3 x s ??

and now i don't have any idea where I am going with this.
 
  • #4
you know that
E = 1/2 m v2, right?

so, in terms of units
J = kg m2 s-2

But W = Js-1 = kg m2 s-3.

But you were asked to find the units of Wm-2, so..
 
  • #5
Maya Erikson said:
1 J = 1 kg x m^-2 / s^-2

and, E = P x t
1 J = 1 W x 1 s

so, 1 kg x m^-2 / s^-2 = 1 kg x m^-2 / s^-3 x s ??

and now i don't have any idea where I am going with this.

Watch your notation! It'll derail you if you're not careful.

J = kg m^2/s^2

A negative exponent "moves" the value between the numerator and denominator. That is,

a^-1 = 1/a

and

1/a^-2 = a^2

What you've written for the units of the Joule would then be:

1 kg x m^-2 / s^-2 = kg*s^2/m^2

Which I'm sure is not what you intended.

Perhaps you meant:

kg*m^2*s^-2
 

1. What is the solar constant?

The solar constant is a measure of the amount of solar electromagnetic radiation received at the outer atmosphere of Earth. It is approximately 1361 watts per square meter.

2. What are the units of solar constant?

The units of solar constant are watts per square meter (W/m2).

3. How is the solar constant measured?

The solar constant is measured using satellites and other instruments that can accurately measure the incoming solar radiation at the top of Earth's atmosphere.

4. Does the solar constant vary?

Yes, the solar constant can vary due to factors such as changes in solar activity and Earth's distance from the sun. However, these variations are very small and do not significantly impact Earth's climate.

5. What is the significance of the solar constant?

The solar constant is an important factor in understanding Earth's climate and weather patterns. It also plays a crucial role in the photosynthesis process, which is essential for plant growth and the production of oxygen.

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