Tom's rocket ship is moving away from Kathy at 0.75c. He fires a laser beam in the backward direction, toward Kathy. According to Galilean relativity. How fast does the laser beam move relative to Kathy, assuming that Tom observes the beam to move away from him at speed c? How fast according to Einstein's relativity? Why?

Solution Preview

According to Galilean relativity, you can add/subtract speeds to find the relative speed. So, in this case you would find that the speed is c - 0.75 c = 0.25 c.

According to special relativity the speed remains c. This is actually a basic postulate of special relativity, so it is wrong to search for explanations of this fact within special relativity itself. Special relativity has two postulates: All inertial frames are equivalent and ...

... Solution: The speed of light beam relative to the ... According to second postulate of relativity" Light propagates through ...speed c independent of the speed of the ...

... He is moving at a speed of 0.6c away from the observer in S, and the signal is moving at the speed of light c, so the relative speed is: c - 0.6c = 0.4c. The ...

... Sol: Yes, the beetle moves relative to the ground ... If it is a very light turntable, we would be able ... on a Ferris wheel that rotates with constant angular speed. ...

... life move so much slower than the speed of light. ... at the differences in measurements between two frames moving relative to one another at a speed of ( or ...

... relativity is well approximated by Galilean relativity for frames having small relative speeds. ... Consider a source of light moving at speed v relative to an ...

... special relativity is that the speed of light in any ... v is the speed of the moving frame relative to the ... negative sign of the laser beam's speed - the spaceship ...

... the seven frequencies present in the sun light equally ... Solution: i) If the speed of the cannon fired ... centre, the observer will indeed measure different speeds. ...

... away at 0.6 of the speed of light. A time T' measured in a moving system (galaxy) is related to the time T measured by a relative stationary observer (on earth ...

... is watching Anna ﬂy by in her high-speed plane, which ... According to Bob, the lights come on at different ... Suppose muons are traveling at 0.930 relative to Earth ...

... following sentence: The various colors of visible light differ in. ... only b. Wavelength only c. Their speeds in a ... and wavelength e. Frequency and their speed in a ...