Fluid Mechanics

Question 1

air resistance

Answer 1

the force acting to oppose the motion of a body through air

Question 2

drag

Answer 2

the force acting to oppose the motion of a body through a fluid

Question 3

factors impacting the magnitude of fluid friction

Answer 3

velocity, mass, frontal cross sectional area, streamlining and shape, surface characteristics

Question 4

velocity

Answer 4

• the greater the velocity, the greater the air resistance or drag
• ineffective reducing velocity so AR or D are reduced by manipulating other factors

Question 5

mass

Answer 5

• greater mass, less it’s motion changed by these forces
• bodies w/ small mass slow down quickly due to fluid friction so AR decreases due to reduced velocity

Question 6

frontal cross-sectional area

Answer 6

• the area of the body presented first to the fluid its moving through
• smaller this area, the less fluid friction
• golf ball has a smaller frontal cross-sectional area than a football

Question 7

streamlining and shape

Answer 7

• minimised by using the optimal shape or position, reduces turbulence and smoothes the air or water flow around a body

Question 8

surface characteristics

Answer 8

• the smoothness of the surface of a body, smooth surfaces create less AR or D than rough surfaces
• e.g. shaving body hair, wearing tight Lycra suits