definitions Flashcards
fundamental units
seven basic units of the SI measurement system: kilogram, second, mole, metre, ampere, Kelvin, candela
accuracy
how close a measurement is to the accepted value (measure of correctness)
precision
agreement among the number of measurements made (how large is the range, measure of exactness)
random error
produced by unknown/unpredictable variations e.g. temperature changes, estimations when reading instruments
can be decreased by increasing no. of trials
systematic error
associated with a particular instrument or experimental technique causing the measured value to be off the same amount each time. e.g. consistently reading the volume wrong
vector
a quantity with both a magnitude and direction
scalar
a quantity with magnitude only
displacement (s)
distance traveled in a particular direction
velocity (u, v)
rate of change of displacement
speed (u,v)
rate of change of distance
acceleration (a)
rate of change of velocity
Newton’s first law of motion
an object at rest remains at rest and an object in motion remains in motion at a constant speed in a straight line unless acted on by an unbalanced force
Newton’s second law of motion
an unbalanced force will cause an object to accelerate in the direction of the net force. the acceleration of the object is proportional to the net for and inversely proportional to its mass
Newton’s third law of motion
when two bodies A and B interact, the force that A exerts on B is equal and opposite to the force that B exerts on A
translational equilibrium
net force acting on a body is zero
linear momentum (p)
product of mass and velocity
impulse (J)
change in momentum
law of conservation of linear momentum
the total momentum of an isolated system remains constant
work (W)
the product of a force on an object and the displacement of the object in the direction of the force
kinetic energy (Ek)
Ek=1/2 mv^2
principle of conservation of energy
the total energy of an isolated system remains constant OR energy can neither be created nor destroyed but only transformed from one form to another or transferred from one object to another
elastic collision
a collision in which kinetic energy is conserved
inelastic collision
a collision in which kinetic energy is not conserved
power (P)
the rate at which work is done OR the rate at which energy is transferred