How Does Light Reflect from a Moving Rocket?

Click For Summary
SUMMARY

The discussion focuses on calculating the time it takes for a light signal to be reflected from a mirror by a rocket traveling at 0.90c, with a distance of 2.4 * 10^12 m as measured by ground observers. For part (a), the time interval can be calculated directly using kinematics without transformations, resulting in 8.42n * 10^3 seconds. For part (b), observers on the rocket must consider both time dilation and Lorentz transformations to accurately determine the time of the reflected signal's reception. The participants emphasize the importance of correctly applying these concepts to solve the problem.

PREREQUISITES
  • Understanding of special relativity concepts, specifically time dilation and Lorentz transformations.
  • Familiarity with kinematics and the speed of light as a constant.
  • Basic algebra skills for solving equations related to motion and time.
  • Knowledge of reference frames in physics, particularly how they relate to moving objects.
NEXT STEPS
  • Study the derivation and application of the Lorentz transformation equations.
  • Learn about time dilation effects in special relativity with practical examples.
  • Explore kinematic equations for objects moving at relativistic speeds.
  • Investigate the implications of the speed of light as a universal constant in various scenarios.
USEFUL FOR

Physics students, educators, and anyone interested in understanding the principles of special relativity and their applications in real-world scenarios involving high-speed motion.

busted
Messages
24
Reaction score
0
A rocket approaches a mirror on the ground at a speed of 0.90c. The distance D between the front of the rocket and the mirror is 2.4 * 10^12 m, as measured by ground observers, when a light signal is sent from the front of the rocket. When is the reflected signal received by the rocket as measured by
a) the observers on the ground
b) the observers on the rocket?

I tried for a) working out the time interval using the formula and substituting the values known of speed of rocket and distance of rocket from mirror but I ended up with a huge value. The actual answer is given as 8.42n * 10^3 s and I am unaware how to get to this.
Can anybody give me some help?
 
Physics news on Phys.org
any ideas anyone?
 
Which formula is "the formula"? Are you talking about a time dilation formula or a Lorentz transformation? I assume that the light signal is actually traveling at the speed of light. The problem is much like any kinematics problem if you can find all the necessary information in each frame. Basically, you have the rocket's velocity, and you want to know how fast it is going according to the ground. When working part b, watch your distance.
 
i was talking about the time dilation formulca, is this the right one to use?
 
i was talking about the time dilation formulca, is this the right one to use?
 
The first part you actually don't need to do any transformations, if I am reading it right, since all the information given to you is with reference to the ground. Is this the part you got wrong?

Think of it like a regular kinematics problem because the only difference is that the numbers are bigger, but the algebra is the same. It is almost the same as some guy skateboarding, throwing a ball at a wall, and then catching it. Just remember that the light out of the spaceship can't exceed the speed of light!

The second part you will need more than just time dilation.
 

Similar threads

Rocket moving away from the Earth
  • · Replies 38 ·
2
Replies
38
Views
4K
Relativistic Rocket Homework: Express T' in Terms of T, v, c
  • · Replies 2 ·
Replies
2
Views
1K
How Do Lorentz Transformations Affect Clock Readings in a Moving Rocket?
  • · Replies 8 ·
Replies
8
Views
2K
A rocket moves toward a mirror at .8c. My answer conflicts with chegg's
  • · Replies 4 ·
Replies
4
Views
3K
Special Relativity, light down a rocket
  • · Replies 64 ·
3
Replies
64
Views
7K
Special Relativity: Rocket Signal Reception Time and Frequency Shift
  • · Replies 5 ·
Replies
5
Views
2K
Relativistic kinematics: when will a photon and spaceship meet?
  • · Replies 2 ·
Replies
2
Views
1K
Can somebody walk me through this Special Relativity clock sync proble
  • · Replies 13 ·
Replies
13
Views
5K
2 dimensional kinematics involving a rocket
  • · Replies 1 ·
Replies
1
Views
1K
Speed of rocket as viewed from Earth
  • · Replies 4 ·
Replies
4
Views
2K