Going up long, steep grades.
friction
Bicycles give you more gas mileage.
Cars and bicycles.
bicycles and cars
The arn't made of metal because it is too heavy and slows the car down.
Netherlands
No
To make then easier to be spotted by cars.
Depends on where you're at. In Europe and North America - certainly. Some parts of Asia probably have more bicycles and scooters than cars though.
The force that slows down moving objects is friction, the action of two objects rubbing against each other. This scenario illustrates the action of Newton's Second Law.
peristalsis slows down the large intestante
Air Resistance slows the parachute down.