Forces practice

Friday Practice - BFPM

Friction Lab

Partners: Christina and Gavriella
Group 3

Objective Statement:
Our objective was to figure out the which factors affect the force of friction on a two sided block. One side of the block had felt on it while the other side had vinyl on it.

Our Plan:
Our plan was to record the force of friction of the block by adding five different weights to the block in order to control the force of gravity. yes but we were really testing how hard the surfaces press together 

Prediction:
The side of the block with vinyl on it would experience a higher force of friction. what about the Fn?

Apparatus:

• Logger pro
• Weights
• Two-sided block with felt and vinyl

Procedure:

1. First we will set the Force Sensor on Logger Pro to be 10 N
2. We will lay the Force Sensor horizontally on the table and “zero” Logger Pro
3. Then we will connect the block to the Force Sensor and begin collecting data
4. As we collect data, we will hit collect on Logger Pro and drag our object at a constant velocity. why was constant velocity important?
5. We will add to the weight of the object each time to collect 5 data points.
6. We will change the Normal Force by changing the mass of the object we are using each time.

Data Collection:units!

Data Analysis:

VM: As the FN increased in Newtons, the force of friction also increased proportionally.

MM: FF = (0.229 N/N) FN - 0.1907 N

Slope: For every 1 N added, the Force of Friction increased by 0.299 N

Y-int: When the FN is 0 N, the Force of Friction is -0.1907 N

VM: As the FN increased in Newtons, the force of friction also increased proportionally.

MM: FF = (1.0591 N/N) FN - 0.3152 N

Slope: For every 1 N added, the Force of Friction increased by 1.0591 N

Y-int: When the FN is 0 N, the Force of Friction is -0.3152 N

Conclusion: 

In this lab, we were trying to find out the difference between the force of friction between the vinyl side and the felt side of a block in order to show their contrasting forces. To find this out, we tested both sides using a force sensor and adding different amounts of weight each time. Then we would pull the block by the force sensor so that we could measure and record the force of friction each time we tested it. The independent variable in this lab was the normal force (in Newtons). The dependent variable was the force of friction also measured in Newtons.

After doing this lab, we discovered that the slopes from our equations are the coefficients of friction. These tell you about the type of surface the object is on. We also found out from this lab that velocity and surface area do not affect the force of friction. Everyone's graph looked identical to ours: the slope of the felt side was significantly smaller than the slops of the vinyl side. The only differences were the y-intercepts and the number of the slope. Other graphs had different slopes because those other groups might have committed data error such as moving too fast or too slow. The equation for the calculation of the force of friction was Ff = μ Fn(N/N). This lab turned out exactly as we predicted: the vinyl side exhibited a larger force of friction.  I feel like you didn;t talk about how the surfaces pressing harder together affects the Ff.....  

Two people wearing identical shoes can have different forces of friction depending on the surface they are on. For example, a person with the same pair of shoes standing on ice will have a less force of friction, whereas the shoes of a person standing on a mountain side will exhibit a greater force of friction. Likewise, two people wearing different types of shoes will have have the same force of friction if they are on a frictionless surfaces. The coefficients of friction determine how much force of friction an object will feel. The force of gravity and the normal force does not affect this on the other hand. Yes, the normal force DOES affect the Ff,...  when the surfaces press together harder, there is more force of friction.  

One source of error that we had was when we measured the force of friction of the vinyl side of the block. When we were calculating our data, the block was kept riling up. This drastically affected how the block was pulled along. Another error we had was when we pulled the block. Sometimes we pulled it too fast or too slow, which messed up how we calculated the mean of the data. In the future, I am interested in finding out how tension affects the force of friction.

I feel like I am getting better at writing lab reports because they are a lot more thorough and informative. I think I can improve my writing of these reports by being more accurate.

Gravity Lab

Partners: Gavrielle and Christina

Group 3 

Objective Statement:

Our objective was to figure out the force of gravity measured in newtons when different masses measured in kilograms are added to a force sensor.

Our plan:

Our plan was to measure the force of gravity by adding five different weights to a mass hanger in order to calculate the forces in newtons.

Data Analysis:

1. In order to measure the force of gravity, we used the Dual Range Force Censor program via Logger Pro

2. We then added a metal mass hanger to the force sensor, which weighted 50 grams and used the "zero" option to reccaliberate the scale of the sensor.

3. Next we added different weights to the mass hanger and collected the data of the newtons produced. We repeated this step the following masses: 10 g, 20 g, 30 g, 40 g, and 50 g

4. We then converted each weight from grams to kilograms

5. The equation of the data points was Force = (9.1 N/kg)mass + 0.017 N, where 9.1 N/Kg = the gravitational field strength of the Earth and 0.017 N = when the mass is 0 kg

very nice

Data Table:

VM: As the mass increased in kg, the force of gravity in Newtons also increased proportionally

MM: Force = (9.1 N/Kg)Mass + 0.017 N

Slope: For every 1 Kg added, the force of gravity increased by 9.1 N

Y-intercept: When the mass is 0 kg, the force of gravity is 0.017 N. However, the force of gravity should by 0 N but the scale of our data points is close enough already.good

Conclusion/Claims and Evidence:

Weight, or the force of gravity, can be determined by multiplying the given mass of an object by 9.8 N/kg. The difference between mass and weight is that mass is defined as how much stuff is in something, whereas weight is defined as the force of gravity.excellent In this lab, we observed that the almost every other group had similar slopes to ours, which was 9.1 N/Kg. After finding out the average of each slope, we discovered that the earth's gravitational field strength is 9.8 N per every 1 Kg. So no matter where on the earth's surface, the gravitational strength always yields 9.8 N/Kg. So the new equation is Force = (9.8 N/Kg)Mass + 0 N. The y-intercept can be anything close to zero newtons. Light and heavy objects hit the ground at the same time because objects with different masses fall at the same acceleration rate of 9.8 m/s/s. Under the rule of free fall motion, all objects will fall at the same rate of acceleration regardless of their mass. This is because since all objects are within the Earth's gravitational field, they all experience the same amount of force. no not same force that would mean everything weighs the same...  the reason they all fall at same rate, a more massive object has more force on it, which is the same as a less massive object with less force on it...  the more massive object is harder move so it requires more force to move it. 

otherwise, great job!  neat and thorough!  :)

Dueling Buggies Lab (10/8/14)

Partner: Charles Lau
Group 1

Objective Statement:
Our objective was to figure out find out a model which demonstrated at which point two buggy vehicles moving from different directions will meet at. Both buggies moved at different speeds; one moved at a fast constant velocity while the other moved at a slower constant velocity.

Our plan:
1. In order to create the model for our lab, we needed to find the point-intercept equation y=mx+b
2. Our first step was calculating the speeds of both the red buggy - the faster one, and the blue buggy - the slower one
3. We measured out 100 cm on a table and then decided to calculate how long it would take for each each buggy to get across the table from 0 cm to 100 cm.

Data Analysis:
1. We recorded the data of the slow car first. The blue buggy traveled 100 cm in 2.49 seconds
2. Next we recorded the data of the fast car. The red buggy traveled 100 cm in 14.90 seconds.
3. We then calculated the speed of each buggy using the formula speed = distance/time to configure the constant velocities of each car. The blue buggy's slope was 14.90 cm/sec and the red buggy's slope was 40.16 cm/sec  
4. After finding out the slopes of both cars, we proceeded to use our model by setting the red buggy at 0 cm and the blue buggy at 150 cm, which was the given data
5. The equation for the fast red buggy was x = (40.16 cm/sec)t + 0, where t = time and 0 cm = the starting position.excellent!
6. The equation for the slow blue buggy was x = (-14.90 cm/sec)t + 150, where t = time and 150 cm = the starting position. The slope of this equation was negative because the buggy was moving in a negative direction at a slow constant speed.
7. After graphing both equations on a graphing calculator, we discovered that the two buggies intersected at 2.72 seconds when they both reached 109 cm from their opposite starting positions.

Using our Model/Designing a Solution:
With our model, we predicted that the two buggies would meet somewhere between the interval [105 cm, 110 cm] really early into the lab. The fast red buggy's slope was far steeper than the slope of the blue buggy, therefore it would cover more centimeters per second. We also predicted that two buggies would meet somewhere closer to the starting position of the red car rather than near the starting position of the blue one. Our method pretty much synchronized with the data produced, thus we do not believe that it was wrong.  looks great!

Buggy Lab (8/28/14)

Partner: Charles Lau
Group 1

Pre-lab observations:

• Constant speed 
• Positive and negative movement (position)
• Placement on the number line - single point
• Turned around
• Lights up
• Red
• Black wheels
• Flower pattern
• Noise
• Antenna
• Batteries
• Distance

Objective: We are trying to figure out the different positions of the buggy after moving in both a positive and a negative direction. as compared to the time...state both variables

Our plan: Our plan is to measure out six end points with a length of 12 inches each for a total of 72 inches. After that, we will turn on the buggy and place it at the starting position 12 inches away from the first end point. Then we will record the time it takes to get to that end point and then do the same for the other 5 end points.

Trial 1 Data:
units for position ?
      Time (sec)  |    Position

We moved the buggy in a positive direction and recorded data from 0 inches to 72 inches

VM: As the time the buggy traveled increased in seconds, the position of the buggy measured in inches also increased proportionally
MM: Position = (18 in/sec)time - 1 in
Slope: For every one second of time it passes, the buggy's position increases by 18 inches
Y-intercept: When the time is zero seconds, the starting position of the buggy is -1 inch.

Trial 2 Data:
units for position?
     Time (sec)   |    Position

We tested the same experiment, but this time we moved the buggy in a negative direction from the ending point at 72 inches.

VM: As the time the buggy traveled increased in seconds, the position measured in inches decreased proportionately

MM: Position = (-18 inches/sec)time + 87 inches

Slope: For every one second of time that passes, the position of the buggy decreases by 18 inches.

Y-Intercept: When the time is zero seconds, the starting /////position of the buggy is at 87 inches

Conclusion: In the lab, there were many claims and evidence to back our observations. First we observed that the buggy went at roughly the same speed as the buggies from other lab experiments. The reason for this is because almost all the other lab reports showed large slopes, which defined the speed and how fast the buggies went. We also observed that all of the buggies had different starting positions. Most of the buggies from the trials had different y-intercepts, some were positive while others were negative. Finally, we saw that many groups placed their buggies in both positive and negative directions. We observed this because the graphs increased or decreased depending on the data. However, we experienced a number of errors during this trial. The most common error was reaction time when we recorded the data of the buggy's position through the timer of our phones. We cannot say that we precisely recorded the data. can you improve that?  how?  or not?  If I were to improve this lab, I would have changed more than just the change of positive/negative direction of the buggy. For example, I would have added weights and inclined slopes in order to produce even more intriguing yet different trial datas. 

Journal Statement: Overall, this lab was a nice experiment to kick off the new year of Physics. It was easy and straight to the point, although as a class we struggled to stay on task and complete it faster. However, jumping into the topic of constant velocity without going over the basic lab procedures made things tough and a little frustrating at first. I do hope in the future that we can work on more labs as fun as this one was.good!!!

Earth-Moon Lab (8/27/2014)

First, we figured out the length of the diameter through the web, which was exactly 7,918 units!. To make scaling easier, we rounded this number to 8,000. We also found out that to get to the moon from the Earth's position, it would take 238,900 total miles to reach it. To make things easier once again, we rounded the number to 240,000 miles. We discovered that if we lined up 30 planet Earths side by side, their total diameter would add up to the total estimated amount it takes to reach the moon. The figure above shows a scaled down version of what the Earth's distance is in relation to the moon.

Excellent!  Good idea to use the earth as the measuring device!