Question

3 multiple choice 1 point
a rocket leaves a launch pad at liftoff with a great deal of upward momentum. what was initially given downward momentum?
the astronauts aboard the rocket
the entire earth
the launch pad
the expelled fuel

Explanation:

According to the law of conservation of momentum, the total momentum of a closed - system is conserved. When the rocket gains upward momentum, the expelled fuel gains downward momentum. The astronauts are part of the rocket system, the launch pad is fixed to the Earth but the main entity that gains downward momentum due to the rocket's upward thrust (based on the rocket - fuel interaction) is the expelled fuel. The Earth's mass is so large that its momentum change due to the rocket's launch (in the context of this problem's scale) is negligible compared to the fuel's momentum change.

Answer:

the expelled fuel