It depends on the ramps slope.
if it was straight down, the cars would fall down the ramp at the speed of gravity, which is 9.8 meters per second
No. Gravity is NOT speed, it is acceleration. In the absence of air resistance, the car would accelerate at a speed of 9.8 ms-2
The car's mass should have no effect on that speed.
Because a higher ramp gives more potential energy than a shorter one.
yes.. if it matters for a real car then it does for a toy car.. gravity and momentum either way
This is the result of gravity, or the pull earth gives off.
drop down a 89 degree slope, that way it will accelerate at the speed of gravity
Yes Friction between the wheels and the ramp and also friction between the body of the car and the air (unless the car and ramp are in a perfect vacuum) There will be additional friction in the bearings or ball race of the wheel / axle too
how does increasing the height of a ramp affect how far a ball rolls down the ramp
In optimal conditions such as infinite runway, performed in a vacuum, with a constant gravitational pull and a zero friction ramp the car could travel at the speed of light. For anything else it would depend on the ramp and the car. Also at what point you stop calling a ramp a ramp and start calling it a drop.
Changing the slope of the ramp will affect the speed of the vehicle going down it.
Yes. The height of the ramp does affect the speed going down it the higher the ramp the faster the car goes down it