Rain is falling vertically. A man running on the road keeps his umbrella tilted but a man standing on the street keeps his umbrella vertical to protect himself from the rain. But both of them keep their umbrella vertical to avoid the vertical sun-rays. Explain.
Answers
Answer:
Till 12th standard i knew only about Relative velocity but quite recently i came to know that it was just an approximation. Thanks to the Genius Albert Einstein & his theory of relativity.
According to theory of relativity:
In the case where two objects are traveling in parallel directions, the relativistic formula for relative velocity is similar in form to the formula for addition of relativistic velocities.
The relative speed is given by the formula:
When Velocities of A & B are relatively small compare to C (Velocity of light) then the eq. simply becomes
Velocity of Rain or the velocity of running man is negligible (wrt velocity of light).
Now i am not going to solve Vector problem for you. You can find plenty of solutions in this thread (I am pretty sure that you already know how to solve Vector equation of relative motion bcz you are in the next stage . By next stage i mean analyzing physics, relating physics to day to day life).
Hence you have to hold your umbrella according to the resultant velocity
But if you will try to put velocity of light in the above equation it will give you absurd result and that's the beauty of it.
No particle (having mass) can reach velocity of light. Velocity of light in vacuum, is a universal physical constant and independent of frame.
Let us take an example. Let say you are moving with Half of velocity of light. And you have a light source (torch).
The velocity of light coming out from the torch (torch itself is moving with c/2 velocity) will be remain the same for any observer (observer moving with c/2 velocity in same direction or observer standing on groud or observer moving opposite with c/2 velocity).
Hence even if you are running at 99.99% of velocity of light, still you have to hold the umbrella vertically to avoid vertical sun rays.
Please note:
Velocity of light in vacuum, is a universal physical constant and independent of frame => Proof of this statement comes from Maxwell's equation (Vacuum equations, electromagnetic waves and speed of light ) -
Can't put it here due to time constrains....
If you want to know the proof of this equation
Plz let me know. I will update my answer (and i will prove it using 10th standard physics).
The beauty of physics is "You don't have to remember anything".
Both of them keep their umbrella vertical to avoid the vertical sun-rays because the speed of rain is less and the speed of sun-rays is high.
Explanation :
- Consider that you’re moving towards the correct and rain is falling vertically towards down.
- Mistreatment the conception of relative motion it'll be appreciate a condition wherever you’re standing still & rain is falling whereas moving towards the left.
- Therefore the rain can have velocities on each y axis (downwards) and also the x axis (towards left) .
- The resultant speed is given by the resultant of the x Associate in Nursing y parts which is able to be inclined at an angle to the horizontal thus you wish to carry the umbrella tipped.
- It’s identical just in case of the sun except that the speed of light is way a lot of and also the resultant vector is vertical .
Thus, the reason has been explained.