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

**Answer:**

the gravitational force between the satellite and the planet is 32.4 * 10³N

**Explanation:**

It is given that,

Mass of the satellite, m = 6500 kg

Speed of the satellite, v = 6.7 × 10³ m/s

distance to the center of the planet = 9 × 10⁶m

Let F is the magnitude of the gravitational force exerted on the satellite by the planet. The centripetal force is equal to the gravitational force. It is equal to :

= 32.4 * 10³N

the gravitational force between the satellite and the planet is 32.4 * 10³N

Pressure and Temperature.

On a circular nature trail.

As Manny ended up at the same point from where he started after walking 3 miles, he walked in a circle.

**Answer:**

crescent Moon crescent Moon