L20

Question 1

Main types of forces: (8)

Answer 1

Gravity
Ground reaction force
Friction
Fluid resistance
Joint reaction forces
Internal force
Muscle force
Elastic force

Question 2

Friction

Answer 2

Ff= UN
Ff= force of friction
U= coefficient of friction
N= normal force (perpendicular to the surface)

Question 3

Fluid resistance

Answer 3

Air and water resistance
-both greatly affected by density and viscosity

Question 4

Drag vs Lift force

Answer 4

Drag force: always acts to oppose motion
Lift Force: always acts perpendicular (opposite) to the drag force

Question 5

Inertial Force

Answer 5

One body segment can exert force on another segment, causing movement at that second segments without muscle exertion

Question 6

Muscle Force

Answer 6

Muscle can generate only a pulling force

Question 7

Elastic Force

Answer 7

Force applied to a material can result in a change in length of that material
F= k x chnge in s
K= stiffness (constant)
Change in s= change in length