Justin Park, Sean Kim, Paul Wang, Derek Guo

Open Inquiry -Finding Gravity

To determine the value of ‘g’ as accurately as possible.

objective

In a case of free-falling of an object, if the ob-ject is dropping from the known height of the stair with zero initial velocity, then the gravity of the object can be calculated by us-ing the formula,

d=1/2•at2 and the value should reflect closed to the known value of 9.81m/s2.

Hypothesis

Measure tape, tennis ball, timer(stop watch)

Materials

Procedure and Process1. Bring the tennis ball to the certain height on the

stair and measure the height of the tennis ball from the ground.

2. Start the stop watch as soon as you drop the ten-nis ball and stop it when it hits the ground.

3. Record your data.

4. Change the height of the dropping level then re-peat the procedure 1-3 six times.

Sean

DerekJustin

Paul

??

Tennis ball

Background Information

Background Information

We dropped the ball from 7 different displacement

RESULTS AND OBSERVATIONS

1 2 3 4 5 6 7

d(m) 2.0 2.5 3.0 3.5 4.0 4.5 5.0

t(s) 0.56 0.69 0.73 0.85 0.88 0.92 1.00

t̂ 2(s 2̂) 0.31 0.48 0.53 0.72 0.77 0.85 1.00

2d(m) 4.0 5.0 6.0 7.0 8.0 9.0 10.0

RESULTS AND OBSERVATIONS

0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

f(x) = 9.02451722048176 x + 0.984643585850592R² = 0.980223722237542

Gravity inquiry - 2d vs t2

t2 (s2)

2d (

m)

Slope = 9.024

9.024 = acceleration = gravity

Limitation: due to the low displacement, in the case less than 5m, the time the object hitting the ground is relatively short. (does not cover human reaction time to stop the stopwatch.

Error : (assume that there is no air resis-tance), the measure tape was not 100% straight

Human error : the reaction time.

ASSUMPTIONS &LIMITATIONS

Hypothesis In a case of free-falling of an object, if the ob-

ject is dropping from the known height of the stair with zero initial velocity, then the gravity of the object can be calculated by us-ing the formula,

d=1/2•at2 and the value should reflect closed to the known value of 9.81m/s2.

Our result was pretty close to 9.81m/s2

ASSUMPTIONS &LIMITATIONS

Conclusion : Throughout this experiment we were able to find the value of ‘g’ by using the method of free-falling of a tennis ball from varying heights of the stairways . Our results, the slope of the best fit line graph, states that the value of ‘g’ is 9.02m/s2. As we indicated, the limitation and possible error sources prevent us from getting precise value of ‘g’, 9.81m/s2.

Possible suggestion to make this experiment more precise is to increase the displacement(height) and to use high-speed camera to measure the time.

ASSUMPTIONS &LIMITATIONS

The End