Subject: How does gravity control the motion of vehicles and why?

I am choosing to ask this question because I may want to be a scientist. The
reason I am asking is because I want to understand more about how gravity works
and although I already learned about this at school, I did not completely learn
about gravity and it's effect on vehicles. If you would answer my question, I
would greatly appreciate it and thank you for all your time.
P.S. I learned about Motion and Design in the fifth grade and it was extremely
interesting. I worked with cars and my class made cool vehicles and tried to see
how far they would go. Since I had fun with that, I am hoping to be a scientist.
Anyway, I hope you get this message and thank you for this opportunity!!! (I
said when I did this activity, I was in the fifth grade, I still am.)

Re: How does gravity control the motion of vehicles and why?