kins 4100: chapter 12 linear forces part 2

laminar flow

a smooth, unbroken flow of fluid around an object. strive for this, minimizes drag

strain

distortion or change produced as a result of stress

angle of rebound

for a perfectly elastic object, the angle of incidence (striking) is equal to the angle of reflection (rebound)

contact forces: normal reaction

for every action there is an equal and opposite reaction ex. jumper pushes of the ground and the ground pushed back

negative work

force acts in the direction opposite to that of the objects motion

positive work

force acts in the same direction as that of the objects motion

friction is proportional to the...

force pressing two surfaces together. - friction acts parallel to the surfaces and opposite to the direction of motion

rebound

governed by elasticity, mass, and velocity of rebounding surface, friction between surfaces, and angle on contact

coefficient of elasticity

indicates the ability of an object to return to its original shape after deformation

a ball with topspin will...

rebound from horizontal surface lower and with more horizontal velocity. "speed up"

a ball with backspin will...

rebound higher and with less horizontal velocity. "stop or reverse"

more muscle mass.. less muscle mass...

sink float

potential energy

stored energy. the product of the weight of an object and the distance over it can act

stress may take the from of....

tension, compression, bending, torsion

elasticity

the ability to resist distorting influences and to return to the original size and shape

energy

the capacity to do work

kinetic energy

the energy an object has due to its motion

fluid forces: buoyancy

the fluid below an object exerts greater pressure on the object than the fluid above it

weight

the force of gravity is measured as the weight of the body applied through the center of gravity of the body and directed toward the earths axis

stress

the force that acts to distort

contact forces: friction

the force that opposes efforts to slide or roll one body over another. amount depends on the nature of the surfaces and the forces pressing them together

work

the product of force extended and the distance over which force is applied

coefficient of friction

the ratio of the force of friction to the normal force acting between two objects - placing one object on a second and tilt the second until first begins to slide

fluid forces: drag

the resistance to forward motion through fluid

fluid forces: lift

the result of changes in fluid pressure as the result of differences in air flow velocities

law of conservation of energy

the total amount of energy possessed by a body or an isolated system remains constant

fluid forces

water ask air are both fluids and as such are subject to many of the same laws and principles - buoyancy, drag, lift

magnus effect

a ball will move in the direction of least air resistance

archimedes' principle of buoyancy

a body immersed in a liquid is buoyed up by a force equal to the weight of the liquid displaced