Newton's Three Laws

                                      Newton's Three Laws

Everyone knows the famous scientist Newton's interaction with an apple, but do we know what it means?

Law one
Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.
Law two
The relationship between an object's mass (m), its acceleration (a), and the applied force F is F = ma. Acceleration and force are vectors which means the direction of the force vector is the same as the direction of the acceleration vector.
Law three
For every action there is an equal and opposite reaction.

Hover Disc Lab Big question: What gives rise to a change in motion? 

When the hover disc was on, there was little friction between the ground and the disc because of the air being produced by the disc. When the disc was off, it was full of friction because it was in direct contact with the ground. A change in motion is affected by different types of forces, such as friction and gravity.

Real World Connection: Air hockey tables

When we get rid of the friction of the table, the puck can be pushed once and will stay in motion until it hits the side of the table or the opponent's "stick". Just as the first law states, an object at motion will stay in motion until acted upon by another force.

Fan Cart lab: 

BIG QUESTION: 

What is the relationship between mass force and acceleration? 

We first turned on the fan cart and pushed it towards the aluminum ring until it collided. We added different masses to the cart and recorded our data.

Real World Connection: Racing

If a heavy car were to race against a thrown baseball, the car would obviously lose the race, but do we know why? Since the equation for acceleration is F=ma, if we increase the mass, the acceleration will decrease, and if we decrease the mass, the acceleration will increase! This picture is a visual for what I explained.

Fan Cart lab and Hover Disc lab:

In Newton's third law, every action has an equal and opposite reaction, the forces that are the opposites need to be:

• Equal in magnitude
• Opposite in direction
• The same net force

Real World Connection: Baseball

When a baseball is hit by a batter, such as Hunter Pence of the Giants, the ball collides with the bat and is sent flying through the air. The forces interacting in this collision are equal because the force of the bat hitting the ball is equal to the force as the ball hitting the bat. Also, they are going in opposite directions, as you can see in the picture. If a person hits a baseball with a bat with 30N of force (I chose 30 arbitrarily) 30N of force is applied to BOTH the bat and ball, but in opposite vector directions.

Impulse Lab

Impulse: A change in momentum 
                      J=P(after)-P(before)
Big Question: 
What is the relationship between impulse, force, and time during a collision?

For this lab, we used a cart and performed a collision. First we attached our force probe to the LoggerPro and attached one sonic range finder to the LoggerPro. We then zeroed out the force probe and collected our data. We measured the force during the collision and also used the sonic range finders to record the velocity of the carts.  We found the momentum for before and after the collision, as well as finding the velocities. Using these things, we were able to find the impulse of the cart. 

Our whiteboard from after the lab displaying our graphs and the equations we derived

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 The impulse value is very similar to the value of the area underneath our graph. We were able to say that J=FT. This video explains the concept very well.

Real world connection:
In baseball, one of the most important parts of a hitter's swing is the follow through. High speed cameras have shown that the follow through of a hitter's swing increases the time in which the collision occurs. By increasing the time, the change in velocity is also increased due to the equation J=FT. 

Collisions Lab

BIG Questions:

What is the difference between the amount of energy lost in an Elastic Collision v. Inelastic Collision?
What is a better conserved quantity-- momentum or energy?


Pre-Lab:

• scalar - simply values, no direction involved
• vector - magnitude and direction
• Moving to the right or upwards - positive
• Moving to the left or downwards- negative

Types of Collisions:

Elastic

Inelastic 

Explosion

Using two carts, two rangefinders, and a track, my group was able to record some data. We did two different experiments, inelastic and elastic. For the inelastic collision, we pushed the two carts together and they stuck together because of the velcro. For the elastic collision, we pushed the red car with the spring in front and the blue cart with the spring and front together. With this data, we were able to determine that momentum is better conserved than energy because there is a plethora of factors that energy can be lost to.

We found the percent differences in the energy and momentum to determine that momentum is best conserved. We also derived the equation, P=MV where P is momentum, M is mass, and V is velocity.

Real World Connection: 

On 9/14/11, the 39 year old catcher for the Boston Red Sox, Jason Varitek, had one of the most memorable collisions in baseball history. When the runner, Brett Lowrie collided with Varitek, the two players created an elastic collision. This sports science video explains the collision very well.

Rubber Band Cart Launcher

This week in class, we completed the Rubber Band Cart Launcher Lab.

BIG Question: How are energy and velocity related?

Our group's data from this lab.

We were required to build a cart launcher consisting of: a rubber band, a cart, a track, and the air glider system. After pulling the rubber band 1cm, 2cm, 3cm, 4cm, and 5cm. We used  the photogate sensor, and we were able to calculate the velocity in which the cart was traveling. 





Using the data we acquired from the sensor, we created a graph on our iPads using the Vernier Graphical Analysis app. From this graph, we were able to derive the equation: E=1/2(mv^2). To answer the big question, energy and velocity are related in the way that if velocity lowers, so will the energy. 


Also, we learned about kinetic energy (moving) and elastic potential (stored). This video has a really catchy song about kinetic and potential energy!

When I was younger, I used sling shots all the time for a variety of reasons. When a rock is put in the holder and pulled back, work is being done and potential energy is stored. When the holder is released, all of the potential energy is converted into kinetic energy and the rock goes soaring. 

Pyramid Lab

Pyramid Lab

This week in class, we performed an experiment about pyramids and how ramps were used to create them. I really found it amazing how the pyramids were created in times with little to no technology.

Big Question: Is the product of force and distance universally conserved?
Answer: Yes, because the law of conservation of energy.

Before we started the lab, we watched this video to find out more about how ramps were used in ancient Egyptian times. 

We may not notice them, but ramps are all around us in our daily lives.

In the lab, we made 3 different ramps that all had an end height of 11 cm. We were required to figure out the amount of work. We first started off by pulling the car 9cm, (which was the height of the books) and this took 2.5 Newtons. Next we dragged the car on the track 140cm which took .15 Newtons. For our last test, we dragged the car 100cm which took .2 Newtons. We came to a conclusion that the greater the distance, the less force required to pull the car.  Using the formula W=FD, we were able to to answer the big question with, yes, energy is conserved.

Being a skier, I use ramps to jump onto a box, shown in the picture above. The ramp makes it easier for me to get on the box and complete my trick.