This is a forces essay.

1. Vidisha Singh
Name: Vidisha Singh
Forces Experiment

2. Vidisha Singh

3. Vidisha Singh
Name: Vidisha Singh
Partners: Tony, Gyeong Uk
Date of experiment: December 3, 2010
Dropping Different Types of Balls
Aim: To measure the force of different types of balls
Hypothesis: The denser the material of the ball, the higher the force it exerts
onto the force plate which will give us a higher reading on our computer.
Variables:
Input variable: The material of the ball. We will change it by dropping
balls of different materials but same size.
Output variable: The amount of force (Newtonʼs) that the balls exert. We
will measure it by dropping it unto a force plate that will give us a reading
of how much force has been exerted.
Control variables:
Control variable 1: The height. The dropping height will be 80 cm.
Control variable 2: The force plate. We will use the same force
plate.
Control variable 3: The size of the balls would be the same by
keeping the same diameter of the balls.
Materials:
• 1 Force Plate
• 1 Meter stick
• 1 Retort stand
• 1 Leather ball
• 1 Plastic ball
• 1 Rubber ball
• 1 Stand and clamp

4. Vidisha Singh
Method:
1. Gather all the equipments needed for this experiment; (Retort stand, the
balls, stand and clap, the force plate and the meter stick)
2. Set up equipment.
3. Mark out 80 cm from the meter stick
4. Get the software for the force plate
5. Make sure that the force plate works as well as the application
6. Check if the force plate works by dropping something on it and recording
the results.
7. If works, then start out with testing for one of the ball
8. Start out with having the ball 80 cm higher than the force plate.
9. Start recording the measurements by clicking on record at the count of 3.
10. Drop the ball as soon as the counting ends
11. When the ball bounces off the force plate, stop recording
12. Record the results in the table
13. Get ready with the ball for another run
14. Get at least 5 trial run through.
15. Switch to another ball
16. Repeat steps 8-15 with the other two ball at having at leat 5 trial runs for
each one.
17. At the end of the experiment make sure of having 5 trial runs for each ball
18. Get the average of the trials for each ball too.
19. Clean up the experience base and put everything back into where it was
cleanly.
20. Give and check results with members of the group.

5. Vidisha Singh
Data Table:
Dropping different types of ball
Types of Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Average
Balls (N) (N) (N) (N) (N) (N)
Leather Ball 117.2 110.6 114.7 111.2 111.2 112.98
Plastic Ball 173.7 213.7 189.0 182.0 248.7 201.42
Rubber Ball 202.0 194.4 194.4 134.7 145.2 174.14
Graph:
Average
force
of
balls
250
200
Amount
of
Forces
(N)
150
100
50
0
Leather
Ball
Plas0c
Ball
Rubber
Ball
Different
types
of
balls
Conclusion:
From what the results were, the average force (N) of the leather ball was 112.98
N. The plastic ball had the average force (N) of 201.42 N, and for the rubber ball
it was 174.14 N. So looking at the force of each ball, the ball that landed in more
force was definitely plastic ball, followed by the rubber ball and the leather ball
was landed with the least amount of force exerting from it. Every trial we had
except of one, plastic ball landed with more force than others. For example in trial
2, plastic ball landed with 213.7 N, while the leather ball and the rubber ball
landed with 110.6 and 194.4 respectively. But only in trial one, the ball that
landed with the most force was the rubber ball because it landed with 202.0 N,

6. Vidisha Singh
while the leather ball and the plastic ball landed with 117.2 N and 173.7 N
respectively. Hence every trial but one had the same type of result repeatedly.
Concluding that the data resulted was reliable, because there were 5 trials run
through and then averaged out. Our hypothesis was turned kind of proved out to
be wrong, because the ball material, which was denser had the second most
force (N) exerted. But also looking at it its not all dense because its not all
compacted, so it wouldnʼt exactly be fully dense.
Evaluation:
The method used was very good because it was very useful because the steps
written down guided through each necessary steps, and made the set up and the
whole experiment sound easy and helped guide through. I believe that my
method did give me a reliable data since we followed the method and got our
experiment finished. Also because we had mentioned the fact that this
experiment should be repeated 5 times so we have a clear data. The error in my
method was that we only did 5 trial runs, which didnʼt give us an accurate
measurement. So next time we will try to have more trial runs so then we will
have more accurate data provided. Second error that I noticed is when we were
dropping the ball; we hadnʼt exactly been accurate when setting the ball up 80 cm
higher from the force plate. This makes us go off what we had naturally planned,
which then changes one of our control variable to another input variable. So next
time I will try to get it accurate so it drops from 80 cm not any higher or lower.
Another error that we faced was that near the end we realized that we should
have dropped the ball in the center of the force plate because then the force
would have been measured accurately since then it could have measured the
force it dropped better. We believe this because if the ball is on the sides then the
reading are different, as we have noticed. So next time our aim is that we will aim
the ball in the center of the force plate. If we would have to do another
investigation then we would have changed the height of the ball being dropped
from. That would have been the input variable. The control variable would have
been same ball being used throughout the experiment.
The Errors:
Error in Your Method Effect on Your Data Improvement to your method
Only 5 trial runs Not that accurate We could have more trial
runs so we can make sure
that the data is more
accurate
Try to get the ball to fall Because then it records Next time we will try to aim
in the center of the the force exactly right the ball in the center of the
force plate. and then the impact it force plate, so it will record
landed it would be the force accurately.
recorded.
Maybe try to set the It wasnʼt exactly 80 cm Next time we will measure
ball at exactly at 80 cm when we dropped it. So exactly 80 cm high before we
high when throwing. it wasnʼt that accurate. set it to drop.

7. Vidisha Singh