Biomechanical Movement C4.4

Question 1

What is lift force?

Answer 1

A body’s movement perpendicular to the direction of travel

Question 2

How is lift force achieved?

Answer 2

Lift force is achieved by manipulating air pressure acting on an object or air pressures:
- Faster speed = low pressure (airfoil shape causes air to travel further over the top
- speed = high pressure (airfoil shape causes air to travel less distance underneath)

Question 3

What is the angle of attack for a discus?

Answer 3

The angle of attack in direction of motion.
- The optimum angle of release for a discus is 25° - 40° allowing the angle of attack to be sufficient
- if the release angle is too great lift force will reduce and drag for will increase causing stalling

Question 4

What is downward lift?

Answer 4

By pushing the object into the ground, greater frictional forces are created (used by cyclists and F1 drivers)

Question 5

How does downward lift benefit F1 drivers?

Answer 5

• the angle of the spoiler causes air to travel over the top meaning it travels shorter distances
• the air being underneath travels at greater velocity as the pressure is lower

Question 6

How does downward lift benefit cyclists?

Answer 6

• Their bikes are fit for purpose with a light frame, low handlebars, a shielded back tyre which all allows the airfoil shape to be created.
• the air travels over the helmet of the cyclist allowing air to travel a shorter distance and instead lower pressures are created underneath along with frictional forces

Question 7

How does downward lift benefit speed skiers?

Answer 7

• by creating the airfoil shape they manipulate the pressure gradient for faster speeds before they reach the jumping point (faster speed = lower pressure as air travels over the top)
  -they have friction with the ground which allows them to move at higher velocities

Question 8

Explain the Bernoulli principle.

Answer 8

Where air molecules exert less pressure the faster they travel and more pressure when they are slower