304-H: Kinematic Equations 6: Turn Around Problems
Topic Cluster: Kinematics
Topic: Forward and Backwards Kinematics Quantitative
Objective: Solve all kinematic equations in two-directions; use relevant quantities to identify what direction an object is moving and whether is is speeding up or slowing down.
The object turned around if its final velocity
is not in the same direction as its initial velocity, OR
The object turned around if its displacement
is not in the same direction sa its initial velocity.
(Which will occur in the subset of the above cases)
How far did it go before turning around?
The object turns around when velocity = 0,
so if you plug in final_velocity = 0,
then you can find the time and displacement before turning around.
Did the object reach the point where it started?
How long did it take to reach there?
How fast was it moving when it reached there?
An object reaches the point where it started at displacement = 0.
To find the time when it started, plug in displacement = 0 and find the time.
If acceleration is constant, it always takes twice as much time tot run around as to return to its initial point.
If acceleartion is constant, then when it returns to its initial point,
its speed will be ideitncal to its initial speed but it will be moving int
the opposite direction.
When was the object speeding up?
When was it slowing down?
The object is slowing down whenever velcoity and acceleration re in opposite directions.
In problems where an object turns around, this occurs BEFORE the object turns around.
The object is speeding up whenever velcoity and acceleration re in the same directions.
In problems where an object turns around, this occurs AFTER the object turns around.