


Kinematics of 1D Uniformly Accelerated Motions

 Here, 'displacement' refers to that from the starting position.
 When 'Edit vt graph' is selected, the vt graph is capable to be changed
by dragging the red corner points on the graph upward or downward.
 The slope of displacementtime graph is velocity; the slope of velocitytime graph is acceleration. Uniform
acceleration is the case when the acceleration is a constant,i.e. the
velocity changes at a constant rate.
 Negative acceleration is usually called "deceleration". In fact, we need both the
directions of velocity and acceleration to determine whether the object
is speeding up or slowing down. The following table summarizes the four cases:

Velocity

Acceleration

Status

Positive

Positive

Real acceleration (moving in the positive direction and speeding up)

Positive

Negative

Real deceleration (moving in the positive direction and slowing down)

Negative

Positive

Real deceleration (moving in the negative direction and slowing down)

Negative

Negative

Real acceleration (moving in the negative direction and speeding up)

In short, object slows down when the acceleration is opposite to the velocity.









