How big would a catapult need to be to launch a car into orbit?
You might get away with a arm length only 40 miles, if you engineer it just right. The main trick is that you need to get the car 25 miles up BEFORE it gets much over 7000 mph (otherwise the air resistance would burn it up). After that, you need a speed of 17,000 mph to stay in orbit.
Don't know how you're going to keep a 40 mile long arm, with the tip moving at 17,000 mph, from breaking apart from the internal stress.
Impossible - speeding it to orbital velocity in lower atmosphere (required because that is where the power is) would burn it up.
catapults won't work because of the initial impulse destroying the launched object, plus the affects of air resistance