course Phy 201
1.� State the definition of rate of change.vvvv
&&&& the average rate of change is equal to change in A over change in B.
2.� State the definition of velocity.
&&&& The rate of direction of the change in the position of an object
`dg2
3.� State the definition of acceleration.
&&&&The rate of change of velocity with respect to clock time
4.� A ball rolls along a path, moving from position 20 cm to position 50 cm as its velocity increases from 5 cm/s to 15 cm/s.
What is its change in velocity and how do you obtain it from the given information?� &&&& Change in Velocity is 10cm/s. 15-5-10
What is its change in position and how do you obtain it from the given information?� &&&& Change in Position 30 cm. 50-20=30
5.� A ball accelerates from velocity 30 cm/s to velocity 80 cm/s during a time interval lasting 10 seconds.
Explain in detail how to use the definitions you gave above to reason out
the average velocity of the ball during this interval, &&&& 80/30=2.66 cm/s
average velocity is not final velocity / initial velocity
and
its acceleration during this interval.� &&&&
Remember, the main goal is to use a detailed reasoning process which connects the given information to the two requested results.� You should use units with every quantity that has units, units should be included at every step of the calculation, and the algebraic details of the units calculations should be explained.
6. �A �graph trapezoid� has �graph altitudes� of 40 cm/s and 10 cm/s, and its base is 6 seconds.� Explain in detail how to find each of the following:
The rise of the graph trapezoid.� &&&& The rise is 6 seconds.
The run of the graph trapezoid.� &&&& The run is 40/10=4 cm/s
The slope associated with the trapezoid.� &&&& Slope is rise over run 6/4=1.5
The dimensions of the equal-area rectangle associated with the trapezoid.� &&&& height is 25 cm/s and the base is 6seconds.
The area of the trapezoid. &&&& 25*6=150
Each calculation should include the units at every step, and the algebraic details of the units calculations should be explained.
7.� If the altitudes of a �graph trapezoid� represent the initial and final positions of a ball rolling down an incline, in meters, and the based of the trapezoid represents the time interval between these positions in seconds, then
What is the rise of the graph trapezoid and what are its units?� &&&& Base (The time Interval)
What is the run of the graph trapezoid and what are its unit?� &&&& Vf-VO
What is the slope of the trapezoid and what are its units?� &&&& Rise/Run=Slope
What is the area of the trapezoid and what are its units?� &&&& Altitude*Base=Vf+Vo/2*’dT
What, if anything, does the slope represent?� &&&& How step the trapezoid is.
What is the altitude of the equal-area rectangle and what are its units?� &&&& Vf-Vo/2 will give you the altitude of an equal area rectangle. Units are Meters
What is the base of the equal-area rectangle and what are its units?� &&&& Time Interveal in seconds.
What, if anything, does the area represent?� &&&& how many m/s
Each answer should include a complete explanation, reasoned out from the geometry of the trapezoid and the definitions you gave at the beginning.
8.� If the altitudes of a �graph trapezoid� represent the initial and final velocities of a ball rolling down an incline, in meters / second, and the based of the trapezoid represents the time interval between these velocities in seconds, then
What is the slope of the trapezoid and what are its units?� &&&& is Rise over Run Vf-Vo/’d T
What is the area of the trapezoid and what are its units?� &&&& Altitude * base=Vf+Vo/2*’dT
What, if anything, does the slope represent?� &&&& Rise over run which is its slope which then represents how step the trapezoid is.
What, if anything, does the area represent?� &&&& Area represents how much space is in the trapezoid
Each answer should include a complete explanation, reasoned out from the geometry of the trapezoid and the definitions you gave at the beginning.
9.� A ball rolls along a path, moving from position 20 cm to position 50 cm as its velocity increases from 5 cm/s to 15 cm/s.
If its acceleration is uniform, then how long does this take, and what is the ball�s acceleration?� ��&&&& average accelration=Vf-Vo/’dT, 50-20=30cm
You did well with about the first half of this set. On the second half you had a lot of good answers as well as some incorrect or incomplete answers.
You could use a little more work on the the problems indicated below, where you'll find an expanded version of problems 5-9. The original questions are still marked with &&&& at the end. The questions marked with ## break the question into smaller questions, and it is these questions you should answer. You should insert your answers to the questions ending in ## into a copy of these 'expanded' problems and submit them.