# Q & A: Jumping Cars

Most recent answer: 01/13/2015
Q:
what kind of physics is it when you jump a car on a ramp for distance with three diferent size ramps
- casey (age 12)
good sheperd school, barrington nh
A:
When things move in simple motion (like jumping ramps), we call it kinematics. That's basically a fancy word for the study of motion of objects.

When the car jumps off of a ramp, it has motion forward and up. But gravity starts to pull the car down. Using physics, we can figure out how far the car is going to go before it lands based on how high the ramp is, how steep the ramp is, and how fast the car is going.

The really interesting part is that you can look at the car like it was moving in 2 directions. The car is moving forward and it is also moving up & down. Gravity only affects the up & down movement of the car. No matter how far the car goes, it will always land moving forward at the same speed at it started with.

(published on 10/22/2007)

## Follow-Up #1: cars on ramps

Q:
Does that mean that despite changing ramp angles the car will travel the same distance if all other factors are the same?
- Zack (age 11)
Greenville, SC
A:

No, the angle of the upward ramp is important. If it's too level, the car will fall down too quickly. If it's too steep, the car won't move much sideways. The angle for the farthest sideways travel depends on how fast the car is going when it leaves the ramp and how high it is when it leaves the ramp. Perhaps you're wondering whether the angle of the downward ramp matters if you keep the same upward launch ramp. In the simple case where we ignore friction, the angle of the downward ramp doesn't matter.

By the way, the previous answer was a bit simpler than the real world. Air friction will slightly slow down that sideways motion.

Mike W.

posted without vetting until Lee returns

(published on 01/13/2015)