What is the relationship between lift and drag?

What is the relationship between lift and drag?

Drag is the price paid to obtain lift. The lift to drag ratio (L/D) is the amount of lift generated by a wing or airfoil compared to its drag. The lift/drag ratio is used to express the relation between lift and drag and is determined by dividing the lift coefficient by the drag coefficient, CL/CD.

How do you find lift and drag?

Lift-to-drag ratio

1. In aerodynamics, the lift-to-drag ratio (or L/D ratio) is the amount of lift generated by a wing or vehicle, divided by the aerodynamic drag it creates by moving through air.
2. The term is calculated for any particular airspeed by measuring the lift generated, then dividing by the drag at that speed.

Why are lift and drag called aerodynamic forces?

Lift and drag are considered aerodynamic forces because they exist due to the movement of an object (such as a plane) through the air. Thrust is generated by the propeller (engine) and opposes drag caused by air resistance.

What affects lift and drag?

Lift and drag also vary directly with the density of the air. Density is affected by several factors: pressure, temperature, and humidity. At an altitude of 18,000 feet, the density of the air has one-half the density of air at sea level.

How is drag caused?

Drag is generated by the difference in velocity between the solid object and the fluid. There must be motion between the object and the fluid. If there is no motion, there is no drag. It makes no difference whether the object moves through a static fluid or whether the fluid moves past a static solid object.

How can drag be altered?

Motion of the Air Like lift, drag actually varies with the square of the relative velocity between the object and the air. The inclination of the object to the flow also affects the amount of drag generated by a given shaped object.

Does lowering a car reduce drag?

Lowered vehicles are more aerodynamic. There’s less air hitting the wheels and tires (that are not streamlined shapes). This makes these cars faster. BUT, lowering a car too much will actually increase wind drag.

How can you reduce drag on something moving through air?

Answer:

1. Make it more streamlined.
2. Reduce it’s speed (very effective )
3. Reduce it’s cross-sectional area.
4. Add boundary layer blowing.
5. Suck the boundary layer.

What is drag give two examples of a drag force How can we reduce the drag on something moving through the air?

when a airplane move it need to be streamline body to reduce drag because due to high speed air offer a resistance against the motion of plan. 2. Boat in water. 3.

What is meant by streamlined shape?

A streamlined body is a shape that decreases the friction drag between a fluid, such as air and water, and an object that passes through that fluid. Drag is the force which reduces the speed of the motion.

Why objects moving in fluids should have streamlined shape?

Objects moving in fluids face the friction of the fluid that opposes their motion. So Objects moving in fluids must have unique shapes called streamlined shapes to reduce the fluid friction.

Why are objects streamlined?

Objects are streamlined so that they can fly more smoothly through the air. This reduces drag, the force that pushes an aircraft backward. Think of seals, airplanes, and even Olympic swimmers!

How does streamlined bodies acquire a faster speed?

Fast-moving vehicles are given streamline shape as their streamlined shape cuts through the air very easily and thus increased their speed. The streamlined shape is given to aeroplanes in the air and ships in the water to reduce the fluid friction.

Does friction depend on speed?

Friction is a contact force when two surfaces interact. Notice that both of these friction formulas ONLY depend on the coefficient of friction and the normal force. It does not depend the area of contact, it doesn’t depend on the sliding speed.

What is an example of bad friction?

For example, friction between our shoes and the floor stop us from slipping and friction between tyres and the road stop cars from skidding. Friction is sometimes unhelpful. For example, if you don’t lubricate your bike regularly with oil, the friction in the chain and axles increases.

What are 5 examples of friction?

Everyday Examples of Sliding Friction

• Rubbing both hands together to create heat.
• A sled sliding across snow or ice.
• Skis sliding against snow.
• A person sliding down a slide is an example of sliding friction.
• A coaster sliding against a table.
• A washing machine pushed along a floor.
• An iron being pushed across material.