Biomechanics Test #1

Newton’s First Law of motion

an object will remain at rest of in uniform motion in a straight line unless acted upon by an external force

“law of inertia”

Newton’s Second Law of motion

the acceleration of an object it directly proportional to the force applied to it and inversely proportional to its mass

“law of acceleration”

Newton’s Third Law of motion

for ever action, there is an equal and opposite reaction. when one object exerts a force on another, the second object exerts equal and opposite forces on the first

“action-reaction law”

moment

the measure of the tendency of a force to produce rotation about an axis

= force x distance

contact force

two objects physically touch each other

non-contact force

gravitational or electromagnetic forces

compression force

loading, collinear forces acting in opposite directions. the act of pressing together

tension force

collinear forces acting in opposite directions to stretch or pull apart

shear force

a force acting parallel to the surface of an object

torsion force

force that twists a body

ground reaction force

forces that act on the body as the result of its interaction with the ground

equal and opposite to the force the body applies to the ground

first class lever

two forces on either side of the axis. fulcrum is in the middles (see-saw)

ex) atlanto-occipital joint (move head backwards)

second class lever

resistance force is in the middle, with effort force and fulcrum on either side (wheelbarrow)

ex) stand on tip toes

third class lever

both effort force and resistance force are on the same side of the fulcrum (hockey, fishing)

ex) elbow joint