For the orbital speed of a spacecraft we know that

here
M = mass of the planet around which satellite is revolving
r = orbital radius
Now when thruster is used by the spacecraft its speed will change due to which orbital speed will change.
Since here while changing the speed mass of the planet will be same
we can say the speed of the spacecraft will changed by thruster due to which its orbital radius will change
so the correct answer must be
<em>b. the spacecraft will change motion and will maintain this new orbit until the thruster is fired again.</em>
Answer:
<em>The 150 lb woman at 30 mph would experience the greatest force of impact in a sudden collision.</em>
Explanation:
<u>Momentum
</u>
The force of impact exerted on an moving object that suddenly stops or changes its movement is measures by the physics magnitude called Impulse, which can be computed with the formula

Where F is the force and t is the time that force acts to produce the impact on the object. The impulse is also defined as the change in the momentum of the object:

Or equivalently

The question describes four situations where different persons and object suffer impact that make them stop from their moving state. Thus
and the impulse is

We are only interested in the relative magnitudes of each case, so we won't consider the sign in the calculations
Case 1: A 200 lb. man traveling 20 mph

Case 2: A 150 lb. woman at 30 mph

Case 3: A 35 lb. infant at 75 mph

Case 4: A 75 lb. child at 55 mph

By comparing the results, we can see that the 150 lb woman at 30 mph would experience the greatest force of impact in a sudden collision.
Answer:
-47.04
Explanation:
Divide 12 m by 2.5 m/s which equals 4.8s
And then use 4.8s to multiply it with -9.8
4.8(-9.8)= -47.04 m/s
Hope this helped!! :)
I believe the correct answer is C good luck!