Transcript Motion - Terminology

Motion - Terminology
Scalar
• A scalar quantity is a quantity that requires
only a magnitude (size) and appropriate units
for its full description.
• Examples – distance, speed, time
Vector Quantity
• A quantity that requires a magnitude (size),
appropriate units, and a direction for its
complete description.
• Examples – Displacement, velocity,
acceleration, force
Position
• The separation between an object and a
reference point in a particular direction.
Position-Time Graph
• Graph of an object’s motion that shows how
its position depends on clock reading, or time.
Distance
• The separation between two points. This is a
scalar quantity.
Displacement
• A change in position in a particular direction.
Because direction matters, displacement is a
vector quantity.
Speed
• Rate of distance traveled to time interval.
Because speed is distance over time, speed is
a scalar quantity and direction is not
important.
Velocity
• The ratio of the change in position to time
interval over which the change takes place.
Velocity is a measure of displacement over
time and since displacement is a vector
quantity, velocity is also a vector quantity.
Velocity-time graph
• A plot of velocity of an object as a function of
time.
Acceleration
• Change in velocity divided by time interval
over which it occurred.
• Or…rate of change in velocity. In IB Physics, a
“rate of change” refers to a time rate of
change unless otherwise indicated.
• Since change in velocity is a vector quantity,
acceleration is also a vector quantity.