Friction Lab

Big questions: What is friction? How does it relate to the atomic description of the universe? 

How does static friction differ from kinetic friction? 

How we went about investigating the big question: For this lab, we used a shoe to demonstrate the force of friction. We took the mass of the shoe using a force probe. We then placed the shoe on the table and hooked the force probe onto it. We added brass masses to the shoe, and we slid the shoe across the table. We then recorded the force of static and kinetic friction. The maximum force of the peak on the force probe was the static friction, and the mean of the straight line on our force probe was the kinetic friction. We then analyzed our data by graphing the weight of the shoe vs. the static fiction and the weight of the shoe vs. the kinetic friction. We created equations from the forces of kinetic and static friction. 

Answer to the big question: 

Static friction is present when both objects are stationary. It must be overcome to start an object's motion. Kinetic friction is present when one or more of the objects are in motion. Must be overcome to keep an object moving at constant velocity. In the force of friction, the electrons are on the surface and the force must overcome them. The friction increases for rougher surfaces. In this case, friction depended on the shoe's surface and the surface of the table. The coefficient of static friction is always greater than the coefficient of kinetic friction. Slope was the coefficient of friction, which we represented with "Mu."

The equations were: Ffs= "Mu"s Fn

                                Ffk= "Mu"k Fn 

    

Evidence to support conclusions: Slope was the coefficient of friction for our lab. Our data supports the fact that coefficient of static friction is always greater than the coefficient of kinetic friction. Our slope for static friction was .702, while our slope for kinetic friction was .647. 

How I can used what I learned in a new situation: I can use the equations we found for the force of kinetic friction and the force of static friction in other situations. I can use it to find how much force it takes to get an object moving and to keep it moving. I can also use it to find the coefficient of friction, using normal force. 

How this relates outside of class: A real life example would be a hockey player hitting the puck across the ice. The ice has less friction than asphalt would, but it still has so,e friction. at a certain point the puck will come to a stop due to this friction.          

Collision Lab

Big question:

What is a better conserved quantity in a collision- momentum or kinetic energy?

How we went about investigating the big question:

For our lab, we placed two range finders on a track and used two cars. We then conducted two different collisions. For the elastic collision, Weser the carts up with their spring launchers facing each other, and we then pushed the red car to collide into the blue. We recorded the speed of the carts before and after the collision. For the inelastic collision, we set the carts up with their Velcro sides facing so that they would stick together. We again pushed the red cart towards the blue and recorded the speeds of the carts before and after. 

Answer to the big question:

The answer to the big question was that momentum is the better conserved quantity in a collision. 

Evidence to support answer: 

We used  % difference = [(TOTAL ENERGY_AFTER - TOTAL ENERGY_BEFORE)/(TOTAL ENERGY BEFORE)] x 100% to find the amount of energy that left the system. We then used  % difference = [(TOTAL MOMENTUM_AFTER - TOTAL MOMENTUM_BEFORE)/(TOTAL MOMENTUM BEFORE )] x 100 to find how much momentum left the system. We got the following results: 

 For the elastic collision 7.86% difference of momentum lost was less than the percentage lost for the kinetic energy. In the inelastic collision, the 22% of momentum lost was less than the percentage lost for the kinetic energy as well, so in both collisions momentum was better conserved. 

How I can use what I learned in a new situation: 

I can use the equations for percent difference to figure out how much energy or kinetic energy is lost. I can also use the conservation of momentum theory to plug in and find other values such as velocity.

How this relates outside of class:

This relates to the Large Hadron Collider, which is a particle accelerator. Two high energy particle beams are guided around the tube by electromagnets. The magnets are used to squeeze particles together and increase the chances of collision. This relates to the amount of energy and momentum that is needed in order for the particles to collide. 

 

Stretching Spring Lab

Big Questions: How does the force it takes to stretch a spring depend on the amount by which you stretch it?

How can we store energy to do work for us later? 

How we investigated the big question: For this lab, we hooked a spring onto our force probe. We then began to stretch the spring various amounts and recorded the force needed to stretch it. We stretched it 1 cm, 2 cm, 3 cm, 4 cm, and 5cm. We recorded our results in a table. We graphed our data and created a best fit line to derive the slope. The slope is also the k value or spring constant, which tells us how many newtons of force the spring provides for every meter it is stretched. The equation of our line was y= 45.96 x + 2.949. The values we got for the force are in the picture. This formula became Us= 1/2 kx squared. 

Answer to big question: 

We found out that the higher the k value, the stiffer the spring is. The higher the distance stretched,the higher the force required. 

Evidence to support our conclusions: As we stretched the spring farther distances, the force required to stretch it increased as well. We got 3.34 newtons when we stretched the spring 1 cm, but the force increased to 3.916 N when we stretched it 2 cm. 

How I can use this in a different situation:

I can use what I learned about the spring constant in various other situations. I can use the formula for the potential energy of a spring in order to find out how much potential energy the spring has when I know the distance stretched and the force required to stretch it. 

How does this relate outside of class:

 I can use this new knowledge when it comes to car shocks absorbers. I would be able to figure out how much force it takes to compress the spring and keep the car from bouncing up and down. 

Pyramid Lab

The big question:

 

1. What pattern do you observe regarding the relationship between force and distance in a simple machine? 

2. How can force be manipulated using a simple machine?

How we went about investigating the big questions: 

My group and I used a force probe to measure the amount of force it took to pull a 7.5 kg cart up a ramp. For trial one, we began pulling the cart up from where thermal met the edge of the table. For trial 2, we readjusted the position of the ramp on  the books to make the angle larger and again pulled the cart up the ramp. We recorded our results for each trial. Our results were as follows: 

                    Trial 1        Trial 2       Trial 3

Force            .544N       .836N       .646N

Distance        1.29m      1.04m       1.12m

Area              .70176      .86944      .732352

We made bar graphs for each trial and calculated the area. To find the area, we used A=fd. The area is also the same as work. 

Answer to the big question:

We found that the answer to the big question of the relationship between force and distance was an inverse relationship. This means that as force increases, distance decreases and the opposite. E learned that force times distance is the constant of work. Work doesn't change as you change the distance of the ramp used to get to that height.

Evidence to support conclusions: 

The force from trial one was .544 N, but it went up to .836 N for trial 2. The distance also changed from 1.29 m in trial one and 1.04 m in trial 2, so the force went up and the distance went down. This proves the inverse relationship.

How we can use what we learned: We can use the equation force X distance= work to solve problems substituting the values we know in order to find other concepts such as height. 

How this relates outside of class: 

This relates to construction and the building of things because various simple machines are used to lift objects up to big heights. We could find the amount of force it takes a machine to lift an object a certain distance. We could then check our results with with what we found, and the results should show the inverse relationship. 

Mass vs Force Lab

The big question: what is the relationship between the mass of an object and the force needed to hold it in place?

How we investigated the big question: For this lab, my group hung brass masses from a force probe and measured the amount of force needed to support it. We recorded the data for four different masses. We then put plotted our points into a graph. The mass in kilograms was on the x-axis and the force in newtons was on the y-axis. We then created a best fit line. We found the slope using g for the gravitalonal constant and used it for the equation force= 10 N/Kg m+ 0. The gravitational constant varies for each planet.

Answer to the big question: The force it takes to hold an object in place is 10 newtons per each kilogram. 

Evidence of conclusions: For 1000 gram or 1 kilogram brass mass, we got a force of 10. 172 Newtons, which can be rounded to 10 Newtons. As wheel as the fact that we got a force of 5. 546 Newtons for our 5 kilogram or 500 gram brass mass. 

How I can use what I learned in a new situation: I can use what I learned in order to find the force needed to hold an object in place in different situations or on different planets. I can also used what I learned in using the slope in the equation in many other problems. 

How this relates outside of class: This relates to volleyball and how much force it takes to hit the ball over the net. Different amounts of force are required to perform all the different techniques in volleyball.