Ball Toss – “Free Fall”
Objectives: Collect position, velocity, and acceleration vs. time graphs and information for a ball that has been:
Part 1) Dropped from rest.
Part 2) Thrown straight up and falls back down to the same height from which it was first released.
Notes:
To get data:
1) Open the file given to you by your teacher.
2) With your basketball sitting on the floor directly below the detector, zero the motion detector to make the floor the origin by going to “Experiment”, and choosing “Zero…”
3) Next, drop/throw your ball as described in each part being sure to record the following for each part of the objective:
A) y-t, v-t, and a-t graph sketches.
- Sketch only the section of the graphs that correspond to the studied motion.
B) Equations of best fit
- For the y-t graph find the equation of best fit and record the equation below the y-t graph (Hint: it should be quadratic).
- To do this, highlight the appropriate section on the y-t graph, click “analyze”, choose “curve fit.”
- For the v-t graph find the equation of best fit and record the equation below the v-t graph (Hint: it should be linear).
- To do this, re-highlight the appropriate section on the v-t graph, click “analyze”, choose “curve fit.”
- For the a-t graph find the mean (average) acceleration value and record this value below the a-t graph.
-To do this, re-highlight the appropriate section on the a-t graph, click “analyze”, choose “statistics.”
- Compare the constants in the equations and answer questions.
C) A brief verbal description of the motion of the ball (for part 2 give special attention to the magnitude and direction of the velocity and acceleration for all three sections of the balls trip – the way up, the top, and the way down).
D) Do the following for Part 2 only…Use your graphs to analyze and calculate the elapsed time it took the ball to rise to its highest point (after it has left your hands) AND analyze and calculate the elapsed time it took the ball to fall from the highest point back to the same height from which it was released (Hint: “examining” both the y-t & v-t graph will be the most useful here). SHOW YOUR WORK where appropriate.
------
Part 1: Dropped from Rest
A)
B)
y-t graph equation:v-t graph equation:mean (average) acceleration:
______1) How does the slope of the v-t graph compare to the mean acceleration?
______2) How does the v intercept of the v-t graph compare to the coefficient of the “t” term in your y-t graph equation?
______3) How does the coefficient of the “t2” term in your y-t graph compare to the mean acceleration?
C) Briefly describe the motion of the ball AND complete the chart.
Falling BallSign of Velocity
Sign of Acceleration
Part 2: Up and Down
A)
B)
y-t graph equation: v-t graph equation: mean (average) acceleration:
______1) How does the slope of the v-t graph compare to the mean acceleration?
______2) How does the v intercept of the v-t graph compare to the coefficient of the “t” term in your y-t graph equation?
______3) How does the coefficient of the “t2” term in your y-t graph compare to the mean acceleration?
C) Briefly describe the motion of the ball AND complete the chart.
Trip Up / At the Top / Trip DownSign of Velocity
Sign of Acceleration
D)
Position:______Position:______
Time:______Time:______Time:______
Velocity:______Velocity:______Velocity:______
Acceleration:______Acceleration:______Acceleration:______
tup:______tdown:______
______1) How does the time it takes the ball to go up compare to the time it takes the ball to fall back down to the SAME HEIGHT?
______2) How does the initial velocity at the start of the trip up compare to the final velocity at the end of the trip down?