Biomechanics Flashcards
Newton’s first law
a body continues in a state of rest or uniform velocity unless acted upon by external or unbalanced force.
Newton’s second law
A body’s rate of change of momentum is proportional to the size of the force applied and acts in the same direction as the force applied.
Newton’s third law
for every action there is an equal and opposite reaction
Net force
sum of all forces acting on a body
Weight
the gravitational pull that the earth exerts on a body
Reaction
the equal and opposite force exerted by a body in response to the action force placed upon it
Friction
the force that opposes the motion of two surfaces in contact
Centre of mass
the point at which an object or a body is balanced in all directions; the point at which weight appears to act
Stability
the ability of a body to resist motion and remain at rest, and the ability to withstand a force applied and return to its original position without damage.
Fulcrum location
joint
Effort location
muscular force
Load location
weight or resistance
1st class lever
fulcrum is in the middle
2nd class lever
load is in the middle
3rd class lever
effort is in the middle
Mechanical advantage
2nd class levers where the effort arm is greater than the load arm, a large load can be moved with relatively small effort
Mechanical disadvantage
3rd class levers where the load arm is greater than the effort arm, a larger load s required to move a relatively small load