Kinetics

Question 1

What is a Newton?

Answer 1

Measurement of force

Amount of force required to accelerate a 1kg mass at 1m/s/s

Question 2

What are Newton’s three laws of linear motion?

Answer 2

1) inertia - an object will not change its state of acceleration until acted upon by an external force.
2) momentum - force is the produce of mass and acceleration (F=ma)
3) reaction - each force has an equal and opposite reaction force

Question 3

How is centre of mass calculated?

Answer 3

Segmentation - individual body parts weighed from cadavers to assess overall contribution to centre of mass

Question 4

What is Nyquist theorem?

Answer 4

Sampling frequency must be at least twice that of the frequency of what is being measured.

Question 5

How are force platforms calibrated?

Answer 5

With known weights under static loading conditions.

Question 6

How do strain gauges work and what are the pros and cons?

Answer 6

Transforms a force to an electrical signal through elastic deformation of a strain gauge
Accurate
Requires more frequent calibration

Question 7

How do piezoelectric force platforms work and what are the pros/cons?

Answer 7

Piezoelectric material’s crystalline structure produces an electrical charge when compressed which is measured by an attached electrode
Compact
Less frequent calibration
Less accurate measurements