Answer:

Explanation:
Given data
Space vehicle speed=5425 km/h relative to earth
The rocket motor speed=81 km/h and mass 4m
The command has mass m
From the conservation of momentum as the system isolated

Since the motion in on direction we can drop the unit vector direction

Where M is the mass of space vehicle which equals to sum of the motors mass and command mass.
The velocity of the motor relative to the earth equals the velocity of the motor relative to command plus the velocity of the command relative to earth

Where Vmc is the velocity of motor relative to command
This yields

Substitute the given values
This is your perfect answer
It is flexible. Water flow can be adjusted and even conserved according to the need for power. It is safe! Compared with the use of fossil fuels and nuclear energy, hydropower is a much safer system..
Answer:
be mature, it's the only way to be called independent, I will help my parents with doing chores, you will meet new friends
Explanation:
it's just my own understanding
Ride in a car down the street: constant velocity,
come to a red light: negative acceleration,
wait for the green light: zero velocity,
<span>start off again: </span>positive acceleration