Galaxy a is moving away from us with a speed of 0.85c relative to the earth. galaxy b is moving away from us in the opposite direction with a relative speed of 0.55c. assume that the earth and the galaxies are inertial reference frames. how fast is galaxy a moving according to an observer in galaxy b?

The speed of the galaxy A moving according to an observer in galaxy B is 0.95c.

Explanation:

Given that,

Speed = 0.85c

Let is the velocity of galaxy A relative to galaxy B, is velocity of galaxy A relative to Earth and velocity of Earth relative to galaxy B.

Let’s assume that galaxy A is moving to the right,along the +x direction, so its velocity relative to earth is

Galaxy B is moving along the–x axis with a speed of 0.55c relative to earth, so its velocity is

Using velocity additional formula

We need to calculate the velocity of the galaxy A relative to galaxy B

Using formula of relative velocity

Hence, The speed of the galaxy A moving according to an observer in galaxy B is 0.95c.

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min