Due to Gravity AP

Choose from the following:

Galileo's Ramps - Can you dilute gravity to measure with homemade timing devices?
Free falling objects (1)
Phyphox - Go ahead make a sound. (2)
Pendulums and Gravity - by varying the length can you determine the accel of gravity?
Picket Fence
Ticker timer
Column of Magnets
Event of your Own

AP Prescribed practicals

Included in the “Applications and skills” section of the guide is a series of practicals that students must cover either in a laboratory environment or as a simulation. The skills and general techniques associated with these common practicals may be assessed as part of the external assessment. The list of required practicals for physics includes:

Topic 2.1 - Determining the acceleration of free-fall

The data collected:

includes sufficient (a min of 5 data points x 3 trials) relevant quantitative and qualitative raw data that could support a detailed and valid conclusion to the research question.
Appropriate and sufficient data processing is carried out with the accuracy required to enable a conclusion to the research question to be drawn that is fully consistent with the experimental data.
Data processing that determines the relationship between variables by examining the trend-line of a graph, not simply performing calculations on each data point.
The processed data is correctly interpreted so that a completely valid and detailed conclusion to the research question can be deduced.
The focus of this summative practical report will focus on Error analysis.

For each of the following scenarios, please consider the aspects of a graph that can be described:

Points:
1. x-intercept, y-intercept, maximums, minimums
Slope:
1. Ratio of ∆IV to ∆DV
2. Often times a rate (IV / s)
3. Both average slope (rise over run) and instantaneous at a point (derivative).
Area Under the Curve:
1. Product of IV and DV
2. In AP, often either a rectangle or triangle.
3. Integral of the function

Picket Fence - Effect of mass on acceleration of gravity.

Using the picket fence and photogate, determine the relationship btwn time and distance fallen.

For the initial data collection, release the picket fence from approximately 10 cm above the photogate. Once you have an initial set of data, please answer the following:

Questions to consider:

Using ANALYZE - CURVE FIT - POSITION, determine the acceleration of the picket fence.
Using ANALYZE - CURVE FIT - VELOCITY, determine the acceleration of the picket fence.
Suppose you were to release the picket fence from 50 cm above the photogate. Describe any changes to your velocity-time graph.
Suppose you were to hang a variety of masses from the picket fence. Describe any changes to your velocity-time graph.
Suppose you were to 'throw' the picket fence downward (as opposed to dropping it). Describe any changes to your velocity-time graph.
Suppose you were to 'toss' the picket fence upward (as opposed to throwing it downward). Describe any changes to your velocity-time graph.

2. Free Falling Balloons

A basic assumption is that there is a relationship between the height (distance) an object falls and the amount of time. Galileo understood this but lacked the proper technology to accurately time elapsed when an object fell. Using the tech in your cell phone you can explore this phenomena.

Materials:

Phyphox phone app.
small dense object that can be tied to string and dropped repeatedly.
Trigger
Balloons - approx 20

Using the equation below, determine the height of the drop.

Questions to consider:

To make the equation on the left more intuitive for free falling objects, what changes to the variables should you make?
Suppose you were to double the mass of the falling object, how would this affect the time to fall?
To collect the initial data you dropped the mass from height (h). Suppose you were to drop the mass from one half the height (0.5h), how would this affect the time to land? (Use the equation to guide your thinking.
Explain why it is important to use a dense mass to experiment with during this experiment.

3. How High Did you Jump?

A student was attempting to determine his maximum vertical jump. He used a 'Force Plate,' a device that can measure the force exerted over time. A graph of a typical jump is shown below.

According to data collected on the LabQuest, the student was in the air for 0.56 s.

Questions to Consider:

Determine the height to which the student jumped.
Determine the velocity at which the student left the scale.
Suppose you were to jump for twice the initial time, how much higher did you jump?
Sketch a graph of the Force v. Time graph, identify the motion of the jumper at each point in the graph.

4. Free Falling - Beyond Galileo's Tech

Using 'modern-day' technology, dilute gravity using an inclined plane.

Using the Vernier Dynamics Carts, from determining the acceleration of a cart on ramps of 5 distinct angles, determine the acceleration of gravity.

Questions to Consider:

As a thought experiment, when the ramp is flat (0˚), the acceleration of the cart would be ______ and if the ramp were to be turned vertical (90˚), the acceleration of the cart would be ________. How does this relate to the equation derived from the graph.
At a given angle, suppose you were to add mass to the cart, how would this affect the acceleration of your cart?

5. Using a Pendulum to Det. g

Determine Acceleration of Gravity - Pendulum: Using a pendulum, determine the acceleration of gravity using the appropriate equation(s). Using your social contacts, compare your results to those from another part of the Earth.

By varying the length of a pendulum the period of the swing will change. Because the force of gravity and tension are the only forces acting on pendulum, we can determine the acceleration due to gravity from the data.
Using a photogate and the Pendulum Setting to collect your data from the LabQuest. More info about the photogate HERE.

Det g from Pendulum.pdf

Some materials we have collect data:

your phone with one of the following apps:
- Phyphox
- Physics Toolbox
- Arduino Science Journal
- Others?
Stopwatches
Video record event (analyze in LoggerPro / Vernier Video Analysis App)
Ticker timers

Vernier Sensors:

Motion detectors
Photogates
Force Plates
Force Sensors
Rotary Motion Sensor

Equipment:

A multitude of spherical objects
Carts of various sizes and degrees of rolling perfection (friction).
2 air tracks with various gliders
Lots of other materials, just ask.

Uncertainty and Errors Theory

Playlist of 1.2 - Uncertainties and Errors.

physics-01.4-uncertainty-complete.pdf

1.4 - Uncertainty and Errors

I can define and compare the terms precision and accuracy
I can define and compare random and systematic error
I can report a measurement to the appropriate level of precision (decimal places)
I can report a measurement with the proper uncertainty for the instrumentation used
I can determine the number of significant digits in a reported value

physics-01.5-uncertainty-in-calculations-complete.pdf

1.5 - Uncertainty in Calculations

I can calculate the uncertainty of an average taken from repeated measurements
I can define and calculate absolute, fractional, and percent uncertainty
I can determine the uncertainty when adding or subtracting two numbers
I can determine the uncertainty when multiplying or dividing two numbers

How to Treat g in an AP Problem

Which Lands First?

Event of your own

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