Rubber Band Lab

Big Question
1) How can we store energy to do work for us later?
2) How does the force it takes to stretch a rubber band depend on the amount by which you stretch it?


This week, we tested how we are able to store energy that allows work to be done earlier. Used a rubber band, an air track, and an electronic probe.
In our first trial, we did a single look with the rubber bacd and a second trial with a double loop. With the electronic probe, we pulled the rubber band 5 different lengths during both trials.

Trial #1-Single Loop
1 cm = 0.01 m = 0.5 N
2 cm = 0.02 m = 1.1 N
3 cm = 0.03 m = 2.0 N
4 cm = 0.04 m = 2.7 N
5 cm = 0.05 m = 3.3 N

Trial #2-Double Loop
1 cm = 0.01 m = 3.7 N
2 cm = 0.02 m = 5.7 N
3 cm = 0.03 m = 8.8 N
4 cm = 0.04 m = 12.1 N
5 cm = 0.05 m = 13.7 N

Later, we graphed our results. The x-axis equals the distance (m) or the amount stretched and the y-axis equals the force (N).

To find the equation to the lab, we started by finding the slope which equaled 71. After, we used the equation y=mx + b and figured out the equation of the graph was y=71x. Then, we used the variables F  (force), K (constant), and X (distance/m). Therefore, our slope of the line (71) is the constant. Since F andX are directly proportional to each other, we put all our facts together and came up with the equation F=KX or Hook's Law.

Next, we had to find the energy. We noticed that the shape of the line created a triangle instead of a rectangle like in the pulley lab. The area of a triangle is A=1/2BH. We replaced A with U which stands for the elastic potential energy. The base of our triangle (X) is the distance stretched and the height is the force.
U=1/2 KX^2 or U=1/2 X(KX)

Real Life Connection-Resistance Bands

Resistance bands are great examples of elastic bands. It is a simple tool that can be used for exercises. The band varies in resistance depending on the type of exercise. By increasing the distance of the band, you are required to use more force. Therefore explaining that there is a direct proportion between force and distance.

Pyramid Lab

Big Question-Is the product of force and distance universally conserved (a constant in systems other than pulleys)?

We discovered that work is universally conserved! This week, we used a ramp instead of a pulley as our simple machine. We stacked 3 books which came to about 4.2 inches and we used a weighted car that was 750g.

The column for distance represents how far we pulled the weighted car up the ramp. The column for force represents the amount of force used to pull the weighted car. We were able to figure out this number with the electronic probe. The third column represents the amount of work for each trial. To get this answer, we multiplied the distance and force from each trial. Since the numbers were more or less the same, we were able to figure out that work is universally conserved.

Real Life Connection-Skateboarding!

 As an athlete, I want to be the best I can be in whatever sport I play. This means I want to find things to challenge myself to see how good I can get. Like in the X Games, we watch skaters perform amazing stunts in the air! They wouldn't be able to perform all these stunts without the help of ramps. Skaters use ramps of different shapes and sizes to perform different tricks.

Pulley Lab

The BIG Question? How can force be manipulated using a simple machine?What pattern do you observe regarding the relationship between force and distance in a simple machine?

 

In the pulley lab, we were asked to figure out how force can be manipulated using a simple machine. We created a pulley system for the lab. We found out that it takes 2 Newtons to life a brass mass 10 cm without the pulley system. With the pulley system, it only took about 1.22 Newtons to lift the same brass mass 10 cm. When we measured the string, it came out to be about 31 cm. With this information, we found out the force can be manipulated by the distance and the angle of the string to pull the weight.

Our next challenge was to have the force reach around 0.5 Newtons. It was a little tricky but, we were able to manipulate the pulley to reach about 0.554 Newtons using 29 cm of string. By graphing our data, we came to the conclusion that as the force decreases, the distance increases. There is an inverse relationship between force and distance. 

• Simple Machine trade off-distance
• Area of bar graph=energy-->the ability to do work
• work=transfer of energy by applying a force over a distance
• W=Fd
• W-->constant(energy)
• (Joules)=(N)(m)
• No matter how big the distance of the force is, you always use the same amount of energy

Real Life Connection-Elevators

It's a Monday morning. You're extremely tired but, you have to work. Imagine not having the option to use the elevator! You would have to walk up and down many flights of stairs each day. Your day would be 10x worst! The elevator is another version of a pulley system to take you up and down to get to any floor you desired.

Mass-Force Lab

Big Questions-How do we measure force in a reliable and repeatable way? What is the relationship between mass of an object and the force needed to hold it in place?

• The first lab we performed was about "mass vs. force." We measured brass masses ranging from 200g-1000g with a manual and electric probe. We were able to figure out the force of Newtons (N) needed to life the mass. With this data, we created a graph.

• Ms. Tye challenged us to find the relationship between mass and force with the data we collected. To find the slow, we plugged in Newtons (rise) over kg (run) which came out to be 10. We labeled the x-axis with the independent variable or the mass (kg) of brass mass. Then we labeled the y-axis with the dependent variable or the force (N). In the end, we came to the conclusion that M=1/10 Force or F=10M. 10 N/kg is "g" or the gravitational constant on Earth.
• From the lab, I learned that by increasing the mass of an object, more force is required to life tje object. Surprisingly, the gravitational constant is different on each planet. 10 N/kg, the force on Earth, is the weakest of all the planets.

Real Life Connection-Pitching!

Ever wonder how a pitchers have the ability to throw the ball so incredibly fast? Part of the reason is God given talent and hard work. The other part has to do with the relationship between speed and force! Clayton Kershaw of the LA Dodgers pitches the ball in the mid 90s. To get the ball to travel that fast for about 60 ft and 6 inches takes quite a bit of force.