generally a racing BMX is built for speed, hence they are made lighter than normal bikes and also have a bigger sprocket witch enables the driver( back sprocket) to go faster.
yes a car can go faster Than A Cheetah
Faster than you can run, but not faster than you can drive a car.
There's really no telling, as both bikes and cars can be used in such different conditions. In congested city traffic a dedicated bike rider can easily be as fast or even faster than a car, while on the open road a car can easily be 3-4 times faster than even a race rider.
Lose weight.
Yes
It doesn't, if your car is missing a tire, your car slows down and the wayward tire appears to go faster.
depend on its engine
Yes ,A car can go faster than a aeroplane if the jet engine is installed in it.Infact the fastest car achieved a speed of 1369 miles per hour.
Faster than you need to go.
faster than a rickshaw
The more rpms you go the faster it will go.Normally 70cc bikes are around 10,000 rpms