exam 2 Flashcards
energy
the ability to do work
kinetic energy
energy of motion
work energy principle
the net work done on an object equals the change in kinetic energy of that object
potential energy
energy associated with forces that depend on the position or configuration of objects
conservative forces
work done by the force in moving an object from one position to another depends only on the two positions and not the path taken; associated with potential energy
nonconservative forces
work done by them is dependent on the path taken; potential energy cannot be defined
law of conservation of energy
energy can be transformed from one type to another but the total energy of the system remains constant
power
the rate at which work is done or energy is transformed
linear momentum
the product of mass times velocity
law of conservation of momentum
when the net forces on a system of objects is 0, the total momentum remains constant
impulse
average force times the time interval, equal to the change in momentum
elastic collision
total momentum and total energy are both conserved
inelastic collision
momentum is conserved but total energy is not, total inelastic occurs when objects stick together post collision
center of mass
the point on an extended object at which the net force can be considered to act for the purpose of determining translational motion as a whole
angular velocity
the rate of change of angular position the same at any point of a rigid object rotating about a fixed axis
angular acceleration
the rate of change of angular velocity
moment of inertia
depends on the mass of the object and how it is distributed relative to the axis of rotation
law of conservation of angular momentum
if the net torque on an object is zero the angular momentum is constant
statics
the subject concerned with the determination of the forces within a structure at rest
equilibrium
state of an object at rest, the vector sum of all forces and torques must be 0
Hooke’s law
the change in length of an object is proportional to the applied force
density
mass per unit volume
specific gravity
the ratio of the density of the material to the density of water
pascals principle
says that an external pressure applied to a contained fluid is transmitted through that fluid
Archimedes’ principle
states that an object submerged wholly or partially in a fluid is buoyed up by a force equal to the weight of fluid it displaces
laminar flow
streamline; layers of fluid move smoothly and regularly along paths around an object
turbulent flow
flow is not smooth and regular but is characterized by irregularly shaped whirlpools
equation of continuity
states that for an incompressible fluid flowing in an enclosed tube, the product of the velocity of flow and the cross sectional area of the tube remains constant
Av=constant
Bernoulli’s principle
tells us where the velocity of a fluid is high, the pressure is low and vice versa
