1. Device used to slow or stop a vehicle.
2. A toothed instrument or machine for separating out the fiber of flax or hemp by breaking up the woody parts.
3. A machine for bending, flanging, folding, and forming sheet metal.
Device used to slow down or stop the movement of a moving body or vehicle. The mechanically applied caliper brake used on bicycles uses a scissor action to press hard rubber blocks against the wheel rim. The main braking system of an automobile works hydraulically: when the driver depresses the brake pedal, liquid pressure forces pistons to apply brakes on each wheel.
Two types of automobile brakes are used. Disc brakes are used on the front wheels of some automobiles and on all wheels of sports and performance automobiles, since they are the more efficient and less prone to fading (losing their braking power) when they get hot. Braking pressure forces brake pads against both sides of a steel disc that rotates with the wheel. Drum brakes are fitted on the rear wheels of some automobiles and on all wheels of some passenger automobiles. Braking pressure forces brake shoes to expand outward into contact with a drum rotating with the wheels. The brake pads and shoes have a tough friction lining that grips well and withstands wear.
Many trucks and trains have air brakes, which work by compressed air. On landing, jet planes reverse the thrust of their engines to reduce their speed quickly. Space vehicles use retrorockets for braking in space and use the air resistance, or drag of the atmosphere, to slow down when they return to Earth.
Sinonimi: retarding force
1. The act of dragging (pulling with force).
2. The phenomenon of resistance to motion through a fluid; SYN. retarding force.
Resistance to motion a body experiences when passing through a fluid—gas or liquid. The aerodynamic drag aircraft experience when traveling through the air represents a great waste of power, so they must be carefully shaped, or streamlined, to reduce drag to a minimum. Automobiles benefit from streamlining, and aerodynamic drag is used to slow down spacecraft returning from space. Boats traveling through water experience hydrodynamic drag on their hulls, and the fastest vessels are hydrofoils, whose hulls lift out of the water while cruising.