# Kinematics and Gravity Lab: Determining G/ Determining Maximum Height ## Recommended Posts Determining G: News article

This just in! Recently, young physicists at Irondequoit High School have calculated the acceleration due to gravity (g). In doing this, the students were first instructed to use their knowledge on kinematic equations to determine acceleration because of gravity. The students used a tape measure, a ball and a stopwatch to conduct this experiment, performing three trials. First off, the students created a table, filling in what they know. One group in particular came up with data as followed before beginning their experiment: The initial velocity was 0 m/s, and the distance was 2 meters. Then, one student measured out 2 meters with the measuring tape, another student held the ball to the top of the marked tape, and released it, and another student timed this with the stopwatch to the best of their ability. That being said, the students performed this experiment in their three trials. Then, the group began the experiment, coming up with .77 seconds for Trial 1, .67 seconds for Trial 2, and .70 seconds for Trial 3, with an average of .71 seconds. The average time filled up the missing "t" spot for the group. Then, the students used what they knew and used a kinematic equation because they still needed to determine the final velocity before finding the acceleration. This group used the equation: Vf=Vi+at and got an answer of 1.7 m/s as the final velocity. Now that each part was filled, the students could find the object's acceleration due to gravity. With this, they picked another one of the kinematic equations, d=Vit+ 1/2at^2, did some minor adjustments to fit the problem and ended up with an answer of 2.37 m/s/s. The student's final objective was to calculate their percent error, which is the Student's Value- Accepted Value/ Accepted Value. This group filled in their information with units and recorded the answer 75.8%. The error was a little high, but because it it very difficult to time something so quickly perfectly, humans are known to perform such inaccuracy. The experiment was done correctly, however, and they found the acceleration due to gravity as 2.37 m/s/s (based on their data). Nice job to the young physicists at IHS!

Determining the Maximum Height:

NEW Vertical Height Testing for all those volleyball players!

Interested in playing VOLLEYBALL and want to know if you can jump high enough? What's YOUR maximum height? Find out today! Did you know it involves Physics?!

We recently tested a new, very effective experiment at determining a human's maximum height. Students at Irondequoit High School conducted a lab to determine how high everyone in their group can jump in three trials. First, one member of the group would time how long another member is in the air using a stopwatch. Then, using their knowledge on kinematic equations, they calculated their maximum displacement. Before they began, each person took a piece of tape, and reached to their maximum height and placed it onto a wall. The group collected the data of one jumper with .63 s, .89 s, .83 s in all three trials. The average time of the jumper in the air was .78 s. To calculate the displacement, however, the students had to divide that average by 2 because displacement is distance without a direction and how far an object does not travel. With that in mind, they ended up with .39 s. For the second jumper, the group recorded her to have .62 s, .60 s and .61 s in her three trials with the average of .61 s. Dividing by 2, they recorded .305 s. After that, they each measured, with a ruler, in centimeters how far the tape from the person's standing reach to their jumping reach. The first person had an accepted value of 30.5 cm, and the second person has 15.7 cm. Then, they converted each measurement into meters because that is the accurate unit in this type of lab (.305 m and .157 m). The first person in the group was clearly in the air longer and had a higher jump than the second person. Unfortunately, this group had sources of error because they only measured one value of their jumping reach, plus stopwatches and humans are not effectively accurate as well. Anyway, the last objective they had to accomplish was the percent error. The students took their values minus the accepted value divided by the accepted value and the first person has a 27.7% error and the second person has a 94.3 % error. Nothing is ever perfect, that's why they're called experiments! However, it was a fun, different way to compare each others' maximum heights!

Want to compare your maximum height with your friends? Try this experiment with us today and see who can jump the highest and stay in the air the longest! Yay physics.

##### Share on other sites In determining the height of a group members jump by using a stop watch requires the perfection with the stop watch. For example; the member of the group who is timing when the person jumping is in the air must start eh watch exactly when the person jumping leaves the ground and stop the watch exactly when the person lands on the ground. Even this may not make the measurements exact. There is still the possibility that the stop watch itself is faulty or is unable to record time precisely. In addition to all of this it is up to the person jumping not to pull their feet closer to them while jumping. In order to over come issues like this and determine the time that the person is in the air I would use a photo sensor that would be able to record the exact time that the person leaves and hits the ground. In addition to this I would record the distance the person moved their feet after jumping.

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• 11 months later...

The young physicists, Katrina Bruzda, Holly Ferguson, and Leah Warner have calculated the acceleration due to gravity in a new manner! Check this out: they used a soft red ball, and a meter stick and a lovely red stop watch to calculate the acceleration of the red ball. Starting out these girls knew the acceleration due to gravity on earth is 9.81 m/s squared, and they set out to prove this theory true. To do this, each time they set the red ball at the top of the meter stick and recorded the time it took the ball, from the time it dropped to the time it hit the floor. Knowing this new data and the initial velocity of 0 m/s, meaning an object at rest, they could then calculate the acceleration due to the gravity of this lovely red ball. We did 5 trial runs to ensure that they collected the perfect data. With their five trials they calculated the acceleratino using the equation (d=vit+1/2at2) and they substituted each time in for this equation and calculated acceleration for each time trial. And then they averaged each of the accelerations to be 7.52 m/s squared, proving a 23.3 percent error apposed to the 9.81 m/s squared value. Althought their one acceleration of 9.45 was very close to the accepted value, sadly their average of all trails didn't add up to euqal the same thing. The 9.45 trial was very beneficial because we were able to witness the actual physics.

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Breaking news-this just in!

Young physicians in Mr. Fullerton's eighth period class at Irondequoit High School have calculated the acceleration due to gravity! They used materials including a ball, a meter stick, and a stop watch. They measured one meter high and dropped the ball from that distance, while measuring the time it took to hit the ground. After three trials, the students took the average of the three times to come up with 0.45 seconds. These smart students already knew the initial velocity of the ball (0m/s) as well as the distance (1m) and time (0.45s) allowing them to solve for accelration using the kinematic equation d=Vit+1/2at^2. Once the acceration variable was isolated, the students plugged in the information and solved the equation and they got 9.88m/s^2 with only a 0.7% error! What a fantastic discovery!

:wave)

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