Physics 1 11 : Mechanics Lecture 2. Dale Gary NJIT Physics Department. Motion along a straight line. Motion Position and displacement Average velocity and average speed Instantaneous velocity and speed Acceleration Constant acceleration: A special case Free fall acceleration. LAX.
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x = + 2.5 m
x = - 3 m
component of 2-D and 3-D motions.
x1(t1) = + 2.5 m
x2 (t2) = - 2.0 m
Δx = -2.0 m - 2.5 m = -4.5 m
x1(t1) = - 3.0 m
x2 (t2) = + 1.0 m
Δx = +1.0 m + 3.0 m = +4.0 m
is the slope of the line segment between end points on a graph.
Note: we are plotting velocity vs. time
slope of the tangent to the curve
of the velocity-time graph
This same plot can apply to an elevator that is initially stationary, then moves upward, and then stops. Plot vand a as a function of time.
, to find the time
, rearrange to get
a = -g = -9.8 m/s2