## Compassionate Group Title Let's see how smart OpenStudy is. The light from the sun travels 187,000mps It hits earth in 8min. How far away is the earth form the sun given this information? How long would it take a Sakura Blossom falling at 5cm/sec to reach Earth from the Sun? Find the force being exerted by the light upon the Earth and how far the earth moves each year by the implications of light imposed upon Earth. Given the earth weighs: 5.972E24 kg How smart is OpenStudy? Lets see. one year ago one year ago

1. AravindG Group Title

$Speed=\dfrac{distance}{time}$

2. AravindG Group Title

$\LARGE \text{speed of light} =3 \times 10^8$ approx

3. AravindG Group Title

so I guess you can do part 1

4. Compassionate Group Title

>How long would it take a Sakura Blossom falling at 5cm/sec to reach Earth from the Sun?

5. AravindG Group Title

in part 2 you are given the speed and distance ,find time

6. AravindG Group Title

distance is got from part 1 :)

7. Compassionate Group Title

Correct. But you're not given the time at 5cm/s

8. AravindG Group Title

Part 2 asks for the time !!

9. Compassionate Group Title

There is no part 1 and 2. This is all one.

10. Compassionate Group Title

You want to find the distance given the speed and time.

11. ParthKohli Group Title

$\rm force = mass \times acceleration$

12. PeterPan Group Title

Let's see how smart OpenStudy is. --Part 1-- The light from the sun travels 187,000mps It hits earth in 8min. How far away is the earth form the sun given this information? --END Part 1-- --Part 2-- How long would it take a Sakura Blossom falling at 5cm/sec to reach Earth from the Sun? --End Part 2-- Find the force being exerted by the light upon the Earth and how far the earth moves each year by the implications of light imposed upon Earth. Given the earth weighs: 5.972E24 kg I'm sure this was what Aravind meant when he said part 1 and part 2

13. ParthKohli Group Title

Since the mass of light is $$0$$, we can just say that light exerts a force of $$0N$$? I don't know, I am not so good at Physics. I think light does exert some force.

14. AravindG Group Title

@PeterPan thanks .Its always a good idea to break a question into parts :)

15. Compassionate Group Title

In fact, light does move the earth every year. I am asking you to find out given little information.

16. Compassionate Group Title

True, light has no stationary mass, but it has a force. Light can burn things, and that's a form of force.

17. AravindG Group Title

Light (as in photons) carries momentum. Any change in that momentum (such as absorption or reflection), will impart a force. So yes, it can exert a force. @ParthKohli

18. Compassionate Group Title

So, the question stands, how much force is exerted upon the earth each year and as a result moves it back.

19. AravindG Group Title

maybe @JamesJ can enlighten us on this

20. AravindG Group Title

what I can only predict is that the force may be around 1 newton or less,

21. AravindG Group Title

@Compassionate do you have the answer with you ?

22. Compassionate Group Title

I do.

23. JamesJ Group Title

Sure, the sun does exert a radiation pressure on the earth of around 4 microPascals, nearly all of it absorbed. So the force isn't quite as low as 1 Newton, but the acceleration due to it is tiny.

24. AravindG Group Title

I think he needs a numerical answer James

25. JamesJ Group Title

I'm not going to do the calculations here myself. I'll ask the questioner what they know about radiation pressure, and what relations they have that can help. I'm happy to be a thought partner. But not right now; I'm going to bed.