5.4 - Terminal Velocity
Drag and air resistance
- Drag is the frictional force on an object moving through a fluid (a liquid or a gas).
- Air resistance is a type of drag.
- Drag increases as speed increases - the faster an object moves, the more drag acts against it.
- For example, a car has much more drag to work against at 70 mph than at 30 mph, so the engine must provide a larger driving force to maintain that steady speed.
Streamlining and reducing drag
- The most important way to reduce drag is to give an object a streamlined shape.
- A streamlined shape lets fluid flow easily past it, reducing drag.
- A parachute is designed to do the opposite - its shape produces as much drag as possible.
TermDefinition
DragThe frictional force that acts on an object moving through a fluid.
FluidA liquid or a gas, whose particles can move past one another so it can flow.
Air resistanceA type of drag that acts on objects moving through the air.
StreamlinedDescribes a shape that lets a fluid flow easily past it, which reduces drag.