Definitions Flashcards
(81 cards)
Physical quantity
Property of a material or system that can be quantified by measurement
Example: Length, mass, time
Scalar quantity
Physical quantity that has magnitude only
Example: Mass, temperature
Vector quantity
Physical quantity that has both magnitude and direction
Example: Displacement, velocity, force
Random error
Measured values are scattered about the true value with no fixed pattern
Example: Fluctuations in a thermometer reading
Systematic error
Measured values are consistently larger or smaller than the true value
Example: Zero error in a measuring instrument
Accuracy
How close the measured reading is to the true value
Example: A ruler measuring to the nearest millimeter
Precision (of a set of readings)
Determined by the range in values
Example: A set of readings with small variations
Precision (of an instrument)
Determined by the size of the smallest division
Example: A ruler with divisions of 1 mm
Uncertainty
Extent of errors
Displacement
Straight line distance from the start to the finish point in that direction
Distance
Total length of the actual path travelled between the start and finish points
Speed
Rate of change of distance
Velocity
Rate of change of displacement
Acceleration
Rate of change of velocity
Viscous drag force
Force which opposes the relative motion of a body moving through a fluid
Equations of motion
Can only use when: Motion is in a straight line with constant acceleration
Newton’s First Law
An object stays at rest or continues to move at constant velocity unless a resultant force acts on it
Newton’s Second Law
The rate of change of momentum of a body is directly proportional to the resultant force acting on it and takes place in the direction of the resultant force
Newton’s Third Law
When body A exerts a force on body B, body B exerts on body A a force of the same type: equal in magnitude and opposite in direction
Mass
The property of a body which resists change in motion
(The amount of matter/substance in a body)
Weight
The force acting on the body due to a gravitational field
Weightlessness
State where a body experiences no contact forces
Resultant force (Fnet)
Rate of change of momentum
Impulse
The product of average force and time duration of impact