5.6 Fluid Mechanics

Question 1

Drag definitions

Answer 1

Force acting in opposition to direction of motion

Question 2

2 types of drag

Answer 2

Surface drag = friction of surface -> swimmer hairy arm
Form drag = affected by shape -> wearing Lycra

Question 3

Factors affecting drag

Answer 3

1. Velocity of object (car speed)
2. Cross sectional body of object (pointy nose)
3. Shape and surface (f1 car, shaved arms)

Question 4

Bernoulli principle

Answer 4

/_ = angle of attack
-> direction of motion
<- drag

Lift force = longer air time
High velocity air = low pressure on top
Slow velocity air = high pressure on bottom
High to low pressure = lift force
~ needs correct angle of attack (40degrees)
~ aerofoil shape
~ cycling + f1 reverse aerofoil, help keep to the ground