AP Physics 1: Constant Velocity

Position, Displacement, and Distance

Position: location of an object with respect to a chosen coordinate system
Displacement (Δx): change in position; straight-line distance between the initial and final positions, must have + or -
Δx=x_f- x_i
Distance (d): total path length traveled from the starting position to the initial
d= length 1+ length 2+ …….+ length n
Magnitude: the amount of
Initial position: starting position, must have sign + or -
Final position: ending position, must have sign + or -

Distance and Displacement will be the same in magnitude unless the object changes direction

Scalar Quantity- magnitude only (how much)
Ex. Mass, Speed, Volume, Time, Temperature
Vector Quantity- magnitude and direction
Ex. Velocity, force, displacement, acceleration

A motion map represents the position, velocity, and acceleration of an object at various clock readings.

The motion map has the points spaced farther apart, and the velocity vectors are longer, implying that the object is moving faster.

Put a “v” on top of the vector to represent velocity, or “a” for acceleration

Uniform Motion: straight-line motion in which equal displacements occur during any successive equal-time intervals is constant-velocity motion

An object’s motion is uniform if and only if its position-vs-time graph is a straight line

The slope of a position-time graph represents an object’s velocity

In a velocity-time graph “the area under the graph'“ represents the object’s displacement. To find “the area under the graph”: b x h

The position is the most fundamental element

Average Velocity: v=Δx (displacement) /Δt (time)
(must have direction: + or -)
Average Speed: distance (total path length) / time
(does not have direction [scalar quantity])

Average speed is better than average velocity when calculating a long distance/trip. Average velocity is better when calculating short distance/trips

Note