Answer:
Net Force = 0
Explanation:
Causes objects to accelerate. Balanced Forces. Two equal forces push in opposite direction causing no change in motion causing net force = 0.
Answer:
1 second later the vehicle's velocity will be:

5 seconds later the vehicle's velocity will be:

Explanation:
Recall the formula for the velocity of an object under constant accelerated motion (with acceleration "
"):

Therefore, in this case
and 
so we can estimate the velocity of the vehicle at different times just by replacing the requested "t" in the expression:

Mass and distance
If mass is doubled, the force of gravity between the objects is doubled