Answer:
8.6 m/s
Explanation:
We can find the final velocity of the dog by using the following SUVAT equation:
where
u is the initial velocity
a is the acceleration
d is the distance covered
For the dog in the problem, we have
u = 1.5 m/s
And the distance covered is
d = 3.0 m
Therefore, we can re-arrange the equation to find the final velocity, v:
1) In the reference frame of one electron: 0.38c
To find the relative velocity of one electron with respect to the other, we must use the following formula:
where
u is the velocity of one electron
v is the velocity of the second electron
c is the speed of light
In this problem:
u = 0.2c
v = -0.2c (since the second electron is moving towards the first one, so in the opposite direction)
Substituting, we find:
2) In the reference frame of the laboratory: -0.2c and +0.2c
In this case, there is no calculation to be done. In fact, we are already given the speed of the two electrons; we are also told that they travel in opposite direction, so their velocities are
+0.2c
-0.2c