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.
12mph is the same whether you are riding a dirt bike, a bicycle, driving a car, or running. 12mph is also about 3mph slower than a fit person running.
Essentially you're looking at F = ma acceleration, a = the same for both vehicles. The mass, m of a bike is much less than that of a car therefore; The required force to push a bike is much less than that required for a car. Therefore it's easier to push a bike.
Speed doesn't make a big difference. Safety should be the priority In bike there is less safety then car. Obviously car is faster than motor bike.
Yes. The Formula for momentum is Momentum= Mass x Velocity. If the slower car has a larger mass, it will likely have a larger momentum.
These days car or bike is about $150
Yes. If it is heavy it will go slower than a light toy car, if it is light it will movefaster than a heavier car.
Yes
Depends on what you think "a lot" is. A bike will need more space than a person but less than a car. Just take a look at a parked bike someplace and you'll see roughly how much.
Because bike riding beats walking, and bikes are much cheaper than cars, and most Chinese haven't got the money for a car.
Certainly, every solid object does. A bike will need more space than a person but less than a car. Just take a look at a parked bike someplace and you'll see roughly how much.
Vehicle in front of you
The faster car travels at 48 miles per hour The slower car travels at 36 miles per hour 48mph - 36mph = 12mph Therefore, the faster car travels 12 miles per hour faster than the slower car. Note that the question refers to the relative speeds of the cars and not the relative distances.