Biomechanics - newtons laws and technology

Question 1

What is newtons first law

Answer 1

‘law of inertia’

• means that something will either stay still or stay moving unless an external force acts on it. For example, a golf ball will remain still unless a force applied by the golf club makes it move

Question 2

What is newtons second law

Answer 2

‘Law of acceleration’

• when the golf ball above is struck by the golf club the rate of change of velocity of the ball is proportional to the size of the force acting on it by the club.

Question 3

What is newtons third law

Answer 3

“For every action, there is an equal and opposite reaction.”

• when 100m sprinter applies a down and backward action force into the blocks, the blocks provide an equal or opposite up and forward reaction force to the sprinter to drive them out of the blocks.

Question 4

What is the equation to calculate velocity

Answer 4

displacement / time taken = velocity (m/s)

Question 5

What is the equation to calculate momentum

Answer 5

mass x velocity = momentum (kgm/s)

Question 6

What is the equation to calculate acceleration

Answer 6

(final velocity - initial velocity) / time taken

Question 7

What is the equation to calculate force

Answer 7

mass x acceleration = force (n)

Question 8

Define net force

Answer 8

The sum of all forces acting on a body.

If net force = 0, there is no change in motion as the forces are balanced (rest)

If a net force is present, there is a change in motion as the forces are unbalanced (acceleration, deceleration, changing directions)

Question 9

How is weight calculated

Answer 9

mass x acceleration due to gravity = weight (n)

Question 10

What are the vertical forces

Answer 10

Weight

Reaction

Question 11

What are the horizontal forces

Answer 11

Friction

Air resistance

Question 12

Define free body diagram

Answer 12

Its a clearly labelled sketch showing all of the forces acting on a body

Question 13

What are limb kinetics

Answer 13

Studies movement using 3d motion analysis, recording an athlete performing an action. This allows joint and limb efficiency to be evaluated. Coaches could then change techniques to improve performance.

Question 14

What are force plates

Answer 14

Measure the size and and direction of ground reaction forces the athlete and can be used to assess acceleration, work and power.
Also used for posture analysis, rehabilitation and physical therapy.

Question 15

What are wind tunnels

Answer 15

Measure air resistance and has an aim is to improve air flow around an object, streamlining its path.

Objects like helmets are tested by measuring the the forces produced by air.

Question 16

One benefit and two disadvantages to having technology (wind tunnels, limb kinetics and force plate)

Answer 16

Analyses movements intricately

Expensive and tends to be in laboratory so some movements are impossible due to space restrictions