course Phy 121
Good work.
Let me know if anything is unclear.
Physics
clip 13 repeat for all trapezoids under curve / all short time intervals from t0 to
tf
If we know the initial and final velocities over some time interval, and if the rate
which velocity changes is constant, then how do we calculate the displacements over a
series of time subintervals?
Answer: The displacement would be the area of the
trapezoid under the graph. OR the average velocity * 'dt
Physics video clip 14
emphasize adding displacements, mention accumulated area
Having calculated
displacements over all specified subintervals, how do we obtain the total distance moved
from the initial clock time up through the end of each subinterval?
Answer: One of two
ways....we can add the cumulative of all of the segements to get a total distance or we
can take the average velocity * 'dt over the entire segment.
How do we construct a
position vs. time graph from a velocity vs. time graph?
Answer: We can use the velocity
vs. time graph to obtain the 'ds values for each segment. Once we have this data we can
regraph the data using the distance and time.
Physics video clip 15 show generally what
we get from a trapezoid, emphasize how trapezoid tells us when to add and
How do we
symbolically and graphically represent the calculation of the displacement corresponding
to a given initial and final velocity over a given time interval?
Answer: The intial
and final velocities are graphically represented and calculated at the ""average height
of the trapezoid""
How do we know when to subtract and when to add the initial in final
velocities in calculating average rates of velocity change and displacements from initial
and final velocities and time interval?
Answer: The intial and final velocities are not
added or subtracted in calculating the 'ds....This is a commom mistake as the intial and
final velocities are ""averaged"" together to calculate the
area under the graph."