exam 2 4600 Flashcards
(15 cards)
law of acceleration
a force applied to a body causes an acceleration of a magnitude proportionate to the force, in the direction of the force, and inversely proportional to the body’s mass
properties of a force
direction, orientation, magnitude, point of force application, line of action
law of action-reaction
if one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object
free body diagram
simplified sketch of isolated system; indicate all forces external to the system with arrows; do not indicate internal force
law of gravitation
all objects with mass attract one another
center of gravity
a point about which all of the mass of an object is evenly distributed
center of pressure
the location of the ground reaction force under the foot; it is simply the central point of the pressure exerted on the foot
force
a vector quantity that describes the total force acting on the foot
friction
resistance to one body sliding, rolling, or flowing over another body
fluid resistance
both human motion (cycling, swimming) and projectile motion (flight of a baseball) can be profoundly affected by the fluid medium (air and water)
surface drag
friction of fluid (laminar flow); velocity of fluid relative to surface, roughness of surface, surface area of object, properties of fluid
pressure drag
front-back pressure differential causes pressure drag force (turbulent flow)
coefficient of drag
an index of how much drag an object can experience
Bernoulli’s principle
fluid resistance is inversely related to fluid velocity (i.e. lower velocity causes higher pressure)
linear momentum
product of mass and linear velocity of an object
