Newton's 3 Laws of Motion

Big Question #1-What gives rise to a change in motion?

The only thing that can change the motion of an object is a net (unbalanced) force acting on it. This is given by Newton's First Law of Motion, sometimes also called the Law of Inertia.

In the hover disk lab, we learned about Newton's 3rd Law of motion which states that forces are equal and opposite. With the fan underneath the hover disk, we eliminated friction. We used interaction and free body diagrams to record out diagrams to record our data.

Big Question #2-What is the relationship between mass, force, and acceleration?

Later we performed the fan cart lab. We performed 5 different trials using 5 different masses to collide the fan cart with the aluminum ring. With the help of LoggerPro to calculate our slope (acceleration), we concluded that F=ma. The fan cart helped us learn about Newton's 1st and 2nd Law

Overall, we learned that F=ma or Force=Mass X Acceleration. The net force acting on an object will cause acceleration.
 There are also about 6 different types of forces: gravitational, normal, friction, tension, spring, and buoyancy. Interaction and free body diagrams help us explain what's going on in the lab.

Real Life Connection-Jumping!

Newton's 3rd Law of motion is applied to jumping like in basketball. An athlete can jump higher off a solid surface because it opposes his body with as much force as he is able to generate, in contrast to sand or other unstable surface.

Impulse Lab

Big Question
What is the relationship between impulse, force, and time in a collision?

In this week's lab, we collided 2 aluminum rings. One ring was attached to a car and the other on a force probe stand. The rings help to slow down the collision so we could analyze the experiment better. We measured the velocity with the sonic probe.

Data

• Mass of cart=0.25g
• Velocity before collision=0.4833 m/s
• Velocity after collision=-0.4008 m/s
• Area under F v T graph=-0.2580 N/s
• Impulse=area under a F v T graph-->J=Ft OR
• Impulse=change in momentum (Kgm/s)-->J=P final-P initial

Big Question #2
Which ring will bend more? Red car or blue car?

After the lab, we crashed a red car with less mass and a blue car with more mass. Aluminum rings were attached to both of the cars.

The rings bend the SAME amount

In any collision, no matter what the mass, there is an equal and opposite force! Since the red car has less mass, there is a greater change in momentum. Force and time are inversely proportional (increase T, decrease F) but impulse remains constant.

J     =      F      x      T 

(NxS)    (N)          (s)

(Kgm/s) (Kgm/s)  (Kgm/s)

Real Life Connection-Landing in Basketball!

When Michael Jordan goes for a dunk, he later bends his knees when he lands. By bending his knees, it increases the time of him landing which decreases the amount of force created from the force of the floor on his knees. There is an equal and opposite force on his knees and the floor. The impulse will always stay constant.

Collision Lab

Big Questions

• What is the difference between the amount of energy lost in an elastic collision vs. an inelastic collision?
• What is a better conserved quantity-momentum or energy?

In this week's lab, we performed an elastic and an inelastic collision to see how momentum and kinetic energy would be affected. Ms. Tye changed up the purpose of the lab this time! Prior to the lab, we already knew the equation p=mv or momentum=mass x velocity. The purpose of the lab was to prove and understand why momentum is used to analyze collisions. We used two cars with a mass of 0.25 kg each for our experiment. In the elastic collision, the cars collided and bounced off each other due to the spring launchers. In the inelastic collision, the cars collided and stuck together due to velcro. We also learned about scalar and vector quantities. A scalar quantity are simple values without any certain direction (mass, temperature, energy, etc..) A vector quantity measures mass and direction (rightward [+] and leftward [-]) We collected our data on the Vernier program. The dips/ hill represents the car's change in velocity

Here is a chart of both collisions involving velocity, momentum, and kinetic energy.

We also had to find the percent difference for the amount of energy and momentum that entered or left the system.

(total energy after-total energy before/average of total energy before and after) x100

Inelastic Collision

Elastic Collision

• also used for momentum!

We could see that almost all of the energy was lost in the system based on the percent errors. Most of the time, momentum was conserved. Therefore, momentum is better conserved in a collision. Energy is lost due to many factors in a system.

Real Life Connection-Golf!
 When playing golf, the club collides with the tiny golf ball. This is an example of an elastic collision. ENergy is transferred from the club to the ball. We must also remember that energy is lost to many factors in a system and momentum is better conserved.

Rubber Band Cart Launcher Lab

Big Question


How are energy and velocity related?

In this week's lab, we used a photo gate sensor to detect the speed of the glider as it passed through it. The sensor calculates the speed based on how much time the glider blocks the photo gate. We performed 5 trials by stretching the rubber band 5 different distances from 0.1-0.5 meters.

From this lab, I learned that energy is conserved! Energy is transferred from elastic potential energy to kinetic energy. The equation to describe this directly proportional relationship is KE=1/2 (m) (v^2)

Real Life Connection-Archery!
By pulling on the arrow, you are increasing the elastic potential energy. When you release the arrow, the energy transfers and becomes kinetic energy. If you increase the elastic potential energy, you are also increasing the kinetic energy which increases the velocity by which the arrow travels. The KE and the EPE are directly proportional. Energy is not only transferred but, also conserved.

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.