# Tag - acceleration

## Measuring the Acceleration with the g Ball

Galileo claimed that all objects fall toward Earth with the same acceleration. Modern measurements indicate that this acceleration is about 9.8m/s2. Using the G-Ball by Arbor Scientific, you can measure this value and compare the acceleration of other objects with different masses and in different states of motion.

What do I need?
You need a G-Ball, a meter stick, other objects to drop such as a baseball.

What will I be doing?
First, you will measure the acceleration due to gravity by simply dropping the G-ball and getting the time to fall.  Next, you’ll throw the G-ball horizontally at different speed and see if the time of fall changes.  Finally, you will drop the G-ball and a baseball to see which object accelerates more rapidly.

What do I think will happen?
Assume that you drop the G-ball from rest from an initial height of 1.0m.  Use the accepted value of g = 9.8m/s2 and the kinematic equation  to predict the time of fall.  Did you get 0.45s?

If you toss the G-ball horizontally, at different speeds do you think:

1. The time for the fall will increase if the G-ball is thrown faster.
2. The time for the fall will stay the same if the G-ball is thrown faster.
3. The time for the fall will decrease if the G-ball is thrown faster.

If you drop a G-ball and a baseball at the same time which one will hit the ground first?  Again, take a moment to write down your thinking to explain your answer.

What really happened?

1. Following the instructions packaged with the G-ball, use it to time a fall of 1.0m.
2. Repeat this process several times to get an average value.
4. Time the fall for the G-ball tossed horizontally from a height of 1.0m.
5. Repeat this tossing the ball horizontally at several different speeds.
6. Do the values vary more than they did for the dropped G-ball?  Comment on your results and compare them with your prediction.
7. Drop a G-ball and a baseball from the same height at the same time.
8. Repeat this several times until you are sure which one hits the ground first.

What did I learn?
If you found that the time for the fall was about 0.45s, then you have verified the accepted value of the acceleration due to gravity is 9.8m/s2.  Did you discovered that regardless of the speed you threw the ball horizontally the time of the fall was the same?  If so, you have shown that the horizontal motion does not affect the vertical motion.  Finally, if you saw that all objects fall at the same rate, you have verified Galileo’s experiment – just like he supposed did at the Tower of Pisa.

What else should I think about?
Why did you have to be careful to throw the ball horizontally?  What would have happened if you accidentally gave the ball a slightly upward initial velocity?  What about a slightly negative initial velocity?

If the mass of a falling object doesn’t affect its motion, why does a feather fall slower that the g ball?

Catch it in the Web!
The Brainiacs dropped cars to test Galileo’s ideas about falling objects. Check it out!

A feather and a hammer were dropped at the same time on the moon. See the result!

Dr. David Kagan has been at CSU Chico for over thirty years. During this time, Dr. Kagan has served in numerous roles including: Chair of the Department of Physics; founding Chair of the Department of Science Education; and Assistant Dean in the College of Natural Sciences to name a few. He is a regular contributor to The Physics Teacher having had over thirty papers published in the journal. Kagan continues his deep devotion to quality teaching by avidly engaging his students with methodologies adapted from the findings of Physics Education Research. In addition, he has remained true to his lifelong obsession with baseball by using the national pastime to enhance the teaching and learning of physics.

## g Ball

In Stock SKU: P4-4000
\$35.00

## Newton's Apple

In Stock SKU: P1-1019
\$6.50

## Gravity Lab

In Stock SKU: P4-1380
\$12.00

## Go! Motion Sensor

In Stock SKU: P4-2400
\$119.00

## Acceleration Force and Mass

 Students love fast moving experiments, but higher speeds often require higher technology. That can challenge the budget and students’ ability to use the technology. These simple, but highly accurate photogates remove both barriers. No costly computers are needed, and set up is easy. Students literally ‘get up to speed’ fast! Stephen Rea has been teaching physics and honors physics at both the high school and college level since 1980. Currently at the University of Michigan, Dearborn, he was the Michigan State Science Teacher of the year in 1994. Using the Timer & Photogates in the Classroom! Arbor Scientific’s photogates are highly effective for use in multiple experiments, including measuring acceleration and exploring projectile motion and Conservation of Momentum. Here are two examples: Acceleration: The Timer & Photogate system is perfect for measuring the acceleration of an object. This typically requires students to measure the time for the object to pass through each of the two photogates, plus the time to travel between them. The way that these values are displayed on the timer makes it easy for students to capture the data. Conservation of Momentum: Experiments with Conservation of Momentum typically involve determining the speeds of two colliding objects, both before and after the collision. Using the timer memory feature, students can use the photogate system to obtain all four time values with precise accuracy. As an example of how they can be used, the teacher challenges students to use the photo-timer system with gliders on an air track and come up with an experiment that confirms Conservation of Momentum. Required Equipment Timer & Photogates 2.0, and the Car& Ramp Recommended quantity per lab group: 1 Timer & Photogates 2.0 P4-1450 Digital Timer & photogates. No computer required for this simple, intuitive data collection device. Complete set includes Timer, two photogates with cords, AC adaptor, user’s manual, and hard carrying case. Click here to get it >> Recommended quantity per lab group: 1 Car & Ramp 2.0 Lab P4-1405 Experiment with distance, time, velocity and acceleration, Newton’s laws and simple machines. The 120cm ramp attaches to the Workshop Stand at angles up to 65°. Click here to get it >>

## Lab #5.5 Mechanics: Chapter 5 The Big BB Race

 PurposeIn this activity, you will compare the path of a projectile launched horizontally with that of an object in free fall.Discussion Suppose a ball bearing (BB) were launched horizontally at the same time another BB were dropped from the same height. Which one would reach the ground first? Required Equipment Vertical Acceleration Demonstrator, Ring Stand and Base, S Clamp. Download

## Vertical Acceleration Demonstrator

In Stock SKU: P3-3520
\$25.00

## Ring Stand Base with Rod

In Stock SKU: 66-4220
\$17.00

## Clamp Holder

In Stock SKU: 66-8290
\$5.50

## Acceleration and Gravity

When a car is on a ramp, a portion of its weight works to roll it down the ramp. Another portion works to hold it down to the ramp. These two portions, or component forces, are perpendicular to one another and can be found by using the car’s weight and the angle of the ramp. If students wish to calculate the car’s acceleration (as in this lab) they will notice that the mass term cancels out of their calculations, leaving only the angle and acceleration due to gravity. Students will predict the acceleration of a car on a ramp at different angles. Then they will measure the actual acceleration and evaluate their predictions.

Required Equipment
Workshop Stand, Ramp, Car, Bolt, Hooked Masses, Easy Sense Data Logger, 2 Photogates, Balance (electronic or triple-beam).

## Car and Ramp Lab

In Stock SKU: P4-1405
\$185.00

## Timer and Photogates

In Stock SKU: P4-1450
\$279.00

## Hooked Mass Set

In Stock SKU: P1-1000
\$85.00

## Economy Triple Beam Balance

In Stock SKU: 02-7600
\$96.00

## Constant Force and Changing Mass

Chapter 6 Lab #19:
Students will investigate the effect that increases in mass have on an accelerating system.

## Meter Stick 6 pack

In Stock SKU: P1-7072
\$18.00

## 500g Hooked Mass

In Stock SKU: P1-1076-07
\$25.00

## Dynamics Carts (pair)

In Stock SKU: P3-3530
\$55.00

## Economy Triple Beam Balance

In Stock SKU: 02-7600
\$96.00

## Digital Stopwatch Timer

In Stock SKU: 52-3200
\$9.95

## Timer and Photogates

In Stock SKU: P4-1450
\$279.00

## Table Clamp Pulley

In Stock SKU: P1-6115
\$16.95

## No-Stretch Pulley String, 25 meters

In Stock SKU: P1-6110
\$3.75

## Car and Ramp Lab

In Stock SKU: P4-1405
\$185.00

## Physics Workshop Stand

In Stock SKU: P4-1901
\$95.00

## Getting Pushy

Chapter 6 Lab #18:
Students will investigate the relationship between mass, force, and acceleration.

## 2000g/20 N Spring Scale

In Stock SKU: 01-6963
\$5.50

## Gravity and Motion

When a car is on a ramp, a portion of its weight works to roll it down the ramp. Another portion works to hold it down to the ramp. These two portions, or component forces, are perpendicular to one another and can be found by using the car’s weight and the angle of the ramp. If students wish to calculate the car’s acceleration (as in this lab) they will notice that the mass term cancels out of their calculations, leaving only the angle and acceleration due to gravity. Students will predict the acceleration of a car on a ramp at different angles. Then they will measure the actual acceleration and evaluate their predictions.

Required Equipment
Workshop Stand, Ramp, Car, Bolt, Data Logger, 2 Photogates, Hooked Masses, Balance (electronic or triple-beam).

## Timer and Photogates

In Stock SKU: P4-1450
\$279.00

## Physics Workshop Stand

In Stock SKU: P4-1901
\$95.00

## Hooked Mass Set

In Stock SKU: P1-1000
\$85.00

## Economy Triple Beam Balance

In Stock SKU: 02-7600
\$96.00

## Going in Circles

Chapter 10 Lab #34:

Students will use an object on a rotating turntable to determine the relative magnitude and direction of acceleration from different positions.

## Pulley on Rod with Clamp

In Stock SKU: P1-4711
\$21.00

## Rotating Platform

In Stock SKU: P3-3510
\$49.00

## Liquid Accelerometer

In Stock SKU: P3-3525
\$48.00

## Dynamics Carts (pair)

In Stock SKU: P3-3530
\$55.00

## Observing Acceleration with an Accelerometer

Use a liquid accelerometer to observe different types of motion and classify the acceleration. Students will observe straight-line motion (constant velocity and constant acceleration), and then take their knowledge of the water’s behavior to more complex circular and pendulum motion. They will discover the centripetal (toward the center) acceleration of circular motion, and the acceleration toward equilibrium of a pendulum system.

Required Equipment
Liquid Accelerometer, Constant Velocity Car, Dynamics Cart, Spring Scales, String, Rubber Band.

## Constant Velocity Car (Carts)

In Stock SKU: 44-1090
\$8.50

## Dynamics Carts (pair)

In Stock SKU: P3-3530
\$55.00

## Spring Scales (Complete Set)

In Stock SKU: 01-6970
\$35.00

## Roll of String

In Stock SKU: PX-2134
\$3.90

The “Rubber Band” required for this lab is readily available at your local grocery or convenience store and needs to be large enough to wrap around the accelerometer. Each lab group would need one rubber band.

## Acceleration Due to Gravity

The first experiment will use very basic equipment to measure an important quantity, the acceleration of an object in freefall. This is also known as the acceleration due to gravity, or g. The acceleration due to gravity is nearly the same at all points on the earth’s surface, 9.8 m/s2. You will compare your result to this accepted value. The second experiment will use a data-logger and photogates to measure the acceleration due to gravity. The “picket fence” has been used since photogates were developed to measure acceleration. The “pickets” block the photogate in sequence, giving a series of velocity readings. Using the velocities and the times between those velocities, the data-logger (or the student) can calculate the acceleration of the picket fence. The third experiment will use a data-logger and motion sensor (or sonic ranger) to measure the acceleration due to gravity.

Required Equipment
Physics Workshop Gravity Lab, Workshop Stand, Stopwatch, Meter stick, Data-logger with Photogates

Acknowledgements: Thank you to Cary Busby for her work in developing this lab. Cary has been High School Physics teacher and has presented physics related workshops at NSTA conferences and State science conferences around the country.

## Gravity Lab

In Stock SKU: P4-1380
\$12.00

## Physics Workshop Stand

In Stock SKU: P4-1901
\$95.00

## Digital Stopwatch Timer

In Stock SKU: 52-3200
\$9.95

## Meter Stick 6 pack

In Stock SKU: P1-7072
\$18.00

## Timer and Photogates

In Stock SKU: P4-1450
\$279.00