Question

In an intergalactic competition, spaceship pilots compete to see who can cover the distance between two asteroids in the short- est time. The judges are at rest with respect to the two asteroids. From the judges' point of view, a pilot has covered the 3-million- km course in 20 seconds. From the pilots' point of view A. The course is longer than 3 million km, the time longer than 20 seconds. B. The course is longer than 3 million km, the time shorter than 20 seconds. C. The course is shorter than 3 million km, the time longer than 20 seconds. D. The course is shorter than 3 million km, the time shorter than 20 seconds. 24. I Energy in the sun is produced by the fusion of four hydrogen atoms into a helium atom. The process involves several steps, but the net reaction is simply 4'H THe + energy. Given this, you can say that A. One helium atom has more mass than four hydrogen atoms B One helium atom has less mass than four hydrogen atoms.

Answer 1

Answer:

a)  truc is C,  b) correct result is the B

Explanation:

As the speed of the competition is very high, for the judges the speed is

           v = d / t

           v = 3 109 m / 20

           v = 1.5 108 m / s

This is half the speed of light. For these high speeds we must use the relations of special relativity.

For the time          t = to γ

For distance         L = Lo / γ

                            γ = √ (1-v2 / c2)

Own time and distance (to and Lo) corresponds to the observer who is not moving the judges in this case

Let's look for the range value

                     γ = 1 / √ (1 - (1.5 / 3) 2) = 1 / 0.866 = 1.15

The time              t = 20 1.15 = 23 s

The distance       L = 3 10 9 /1.15 = 2.60 109 m

From these results we see that time increases and the distance is shorter.

Let's review the claims

A) False. It's the opposite

B) False

C) True. It is according to the result found

D) False.

In the nuclear fusion process, we will also use the special relativity that has a relationship between energy and mass

         ΔE = c² Δm

As in the process energy is released, for the law of conservation of the mass of energy to be fulfilled, the total mass of the products, He atom, must be reduced.

Therefore the correct result is the B