Chapter+4+1-5

=Chapter 4: Thrills and Chills=

Chapter 4 Section 1

 * What do You see?**
 * Woman is moving a man around in a wheel chair following lines on ground
 * Man is envisioning a roller coaster
 * Lots of change in direction


 * What do you Think?**


 * Which part of the roller-coaster ride produces the loudest screams and why?
 * The drop down produces the loudest screams because of the gain in acceleration going down


 * Roller-Coaster Designs (Homework)**


 * El Toro at Six Flags **
 * Steep Decline
 * Two equal sized hills

Viper at Six Flags Great America
 * Various Loops and Turns
 * Steep Decline then Incline


 * Physics Talk**


 * Distance- a scalar quantity
 * Displacement- a measured distance with a direction included (vector)
 * Has a magnitude or length
 * Speed- the distance traveled by the time elapsed
 * Velocity- the displacement divided by the time elapsed
 * Acceleration- the change in velocity divided by the time elapsed


 * Checking Up**


 * 1. Explain the difference between distance and displacement
 * Distance is a scalar quantity and Displacement is a vector
 * A change in distance (displacement)
 * 2. You went to school and back home, a total distance of 2km. What is your displacement?
 * 0 km
 * 3. What is the difference between speed and velocity
 * Speed- the distance traveled by the time elapsed
 * Velocity- the displacement by the time elapsed
 * 4. How can you find the acceleration of an object?
 * Change in velocity/time elapsed


 * Physics To Go**

1. Draw a top and side view of a new version of the Terminator Express 2. Identify where the biggest thrill would be on this roller-coaster. Explain. 3a. Which city has the greater speed? 3b. Calculate the earths speed at the equator 3c. Why do you not get a big thrill going such high speeds? 4. A roller coaster rider changes speed from 4 m/s to 16 m/s, what is his acceleration 5. Identify the following situations as an example of either distance, displacement, speed, velocity, or acceleration 6. A cart is 10 cm long. It travels through a velocimeter in 2s. Calculate the cart's speed. 7. A second lab cart is 5 cm long. If it were traveling at the same speed as the cart in question 6, what would the velocimeter record as the elapsed time? 8. Your vehicle accelerates from 0 to 25 m/s in 10s while traveling down a straight street. What is the acceleration of your vehicle 10. Suppose you were designing a roller coaster for young preschool children.
 * The Biggest thrill would be either the drop from Hill 1 because you gain a lot of acceleration or the Horizontal loop because of the change in direction
 * La Paz, Bolivia because it has to travel a greater distance over the same amount of time as Oslo.
 * v = 40,000km/24h = 1,666.67 km/hr
 * Because its a constant speed, there is a lack of acceleration
 * 4 m/s squared
 * a. A car traveling at 50km/h
 * speed
 * b. a student riding a bike 4 m/s toward home
 * velocity
 * c. a roller-coaster ride whips around a left turn at 5 m/s
 * velocity, acceleration
 * d. a roller-coaster car is dragged up a hill 12m tall traveling at 3 m/s
 * displacement, velocity
 * e. train ride takes you 150 km northwest
 * Displacement
 * v = d/t
 * v = .1/2
 * v = .05m/s
 * v = d/t
 * .05 m/s = .05/t
 * t =1
 * a = change in v/t
 * a = 25/10
 * a = 2.5 m/s squared
 * a. Describe two changes you would make to The Terminator Express roller - coaster. Explain why you would make these changes.
 * If this was being designed for preschool children, I would take out the clothoid loop and slow the speed on the horizontal loop. I would also make the hills less steep to not scare these beginner roller-coaster riders.
 * b. Draw the top and side view of the roller coaster with these additional changes.
 * [[image:CH4S1PTG.jpg width="448" height="336"]]


 * What do you Think Now?**


 * Which part of the roller-coaster produces the loudest screams? Why?
 * The descend from the big hills cause the loudest screams because of the acceleration. Also the horizontal loops because of the acceleration gained. They will produce the biggest thrills because acceleration causes thrill!

Chapter 4 Section 2

 * What do you See?**


 * Steeper Cart going faster and kids having more fun
 * The other cart is going slow and they are falling asleep


 * What do you Think?**


 * Which roller coaster will give the biggest thrill? Why?
 * The steel one will give the biggest thrill because it has the steeper slope allowing for more acceleration


 * Physics Talk**


 * GPE- is the energy an object has as a result of its position in a gravitational field
 * KE- the energy an object possesses because of its motion, in particular due to speed
 * Joule- (J) unit for energy
 * Mechanical Energy- The Sum of GPE and KE


 * Checking Up**

1. What effect does changing the length of the incline have on the speed of a ball when it rolls to the bottom 2. How does the gravitational energy of an object change with its height? with its mass? 3. How does the kinetic energy of an object change with its speed? with its mass 4. As a roller-coaster car rolls down a hill, what happens to the gravitational potential energy it loses 5. If a roller-coaster car has 40,000J of GPE when rest on the top of a hill, how much KE does it have when it is 3/4 down the hill?
 * It increases the speed
 * Its GPE increases in both cases
 * Changes both instances .5mv^squared
 * It gets transferred to kinetic energy
 * 30,000J


 * Physics To Go**

1. For which track is the speed of the car the greatest at the bottom 3. Complete the table below for a roller coaster starting from rest at the top. > || top (30m) || 60,000 || 0 || 60,000 || > || bottom (0m) || 0 || 60,000 || 60,000 || > || halfway down (15m) || 30,000 || 30,000 || 60,000 || > || 3/4 way down (7.5) || 15,000 || 45,000 || 60,000 || 4. Draw a GPE and KE energy bar chart for Q3
 * Both cars have the same speed at the bottom because their initial height is the same
 * || height (m) || GPE =mgh || KE = 1/2mv^2 || GPE + KE ||
 * [[image:CH4S2_PTG.jpg width="511" height="383"]]

8. Will the speed of the roller coaster change with more passengers aboard 9a. At which point is the roller-coaster car traveling the fastest? 9b. At which two points is the roller-coaster car traveling at the same speed? 9c. Is the roller-coaster car traveling faster at E or D
 * The Speed will not change because of the mass because mass is independent. This means it will cancel out in with GPE and KE
 * The roller-coaster is traveling fastest at point B because its initial height was the highest before the drop.
 * The roller-coaster is traveling at the same speed at points C and F because their heights are the same.
 * The roller-coaster is traveling faster at D because it just dropped from C, rather than traveling up from D


 * What do you Think Now?**


 * Which roller-coaster will give the biggest thrill
 * The one with the steeper hill because they both start at the same height, and mass does not play a role and there is more acceleration on the steeper hill. The GPE gets converted to KE faster.

**Chapter 4 Section 3**

 * What do you See?**
 * kids launching frog with spring into the air
 * girl measuring it with a photo-gate timer


 * What do you Think?**


 * How does the roller coaster today get up to its highest point?
 * I believe it is carried by chains and springs. This is because the roller coaster has not even started moving so something needs to start it
 * Does it cost more to lift the roller-coaster if it is full of people
 * I believe so because people add weight to the roller-coast; therefore, more power is needed to operate it


 * Physics Talk**


 * Spring Potential Energy - Same as Elastic Potential energy (Springs, bungee cords, trampolines)
 * Before Pooping- SPE is full, GPE and KE are at their lowest
 * Just after leaving table- NO SPE, Some GPE,
 * Halfway Up- Half GPE and KE, NO SPE
 * At the Top - FULL GPE, NO KE or SPE


 * Checking Up**

1. What happens to the SPE of a pop-up toy, after its off the table 2. A "pop-up" toy has 2J of SPE before popping. How much kinetic energy will the toy have just after leaving the table 3. A "pop-up" toy has 2J of SPE before popping. How much KE will it have at the top? 4. What two factors determine the amount of SPE stored in a spring
 * it fully drops. There is none left
 * 2J
 * 0J
 * the amount of stretch or compression


 * Physics To Go**

5. Why can the second hill of the roller-coaster not be higher then the first hill? 6. Why does the roller-coaster not continue forever and not go up and down all over again 7. A roller-coaster of mass 300 kg ascends to a height of 15 m. How much electrical energy was required to raise the carts to this height 8. A roller-coaster has a mass of 400 kg and a speed of 15 m/s. 9. A ball is thrown upwards from the earths surface. While the ball is rising, is its GPE increasing, decreasing, or the same? 10. Who has most GPE, path A, B, or C? 11. The mass of spring toy was .020 kg. The height of the toy rose to .40m. The initial speed of the spring toy as measured by the velocimeter was 2.7 m/s 12. A roller-coaster begins at a height of 18 m. The mass with the passengers is 300 kg. >> 13. An umbrella has an automatic opening mechanism. When the umbrella is closed, the spring is compressed. The Spring constant is 40 N/m and the spring is compressed .3m. What is the KE of the umbrella when it begins to open?
 * Because the GPE of the first hill is not equal to the GPE in the second and there is not enough energy to go over the second hill.
 * Because friction is present and is a force that creates work. Work takes away from the other forms of energy and there is less energy to create KE and GPE
 * GPE = mgh
 * GPE = (300)(9.8)(15)
 * GPE = 44,100 J
 * a. What is the KE of the roller-coaster?
 * KE = .5mv^2
 * KE = .5(400)(15)^2
 * KE = 45,000 J
 * b. What will the GPE of this roller-coaster car be at its highest point, where KE = 0 at that point?
 * 45,000 J
 * c. How high can a roller-coaster go with this much energy?
 * 45,000 J = GPE
 * 45,000 J = mgh
 * 45,000 J = (400)(9.8)h
 * 11.48 m = h
 * Increasing
 * At different points, the GPE of the paths could be different, but at the end, the all end up in the same area; therefore, the GPE is the same for all paths.
 * a. Does the GPE and the KE both give approximately the same values?
 * yes, GPE = .0784J; KE = .0729J
 * b. What is the SPE before the toy pops?
 * SPE = KE
 * SPE = .5mv^2
 * SPE = .5(.020)(2.7)^2
 * SPE = .0729J
 * c. What height do you expect the toy to reach if the mass was tripled?
 * KE = GPE
 * .5mv^2 = mgh
 * .5(.006)(2.7)^2= (.006)(9.8)h
 * h = .37m
 * a. What must be the spring constant of this spring if it will be compressed by 4m?
 * GPE = EPE
 * mgh = .5kx^2
 * 300(9.8)(18) = .5k(4^2)
 * k = 6,615 N/m
 * b. How much will the spring compress if an additional 100kg of people are aboard?
 * GPE= SPE
 * GPE= mgh
 * 400(9.8)(18)= 70,560 J
 * 70,560= .5kx^2
 * 70,560= .5(6,615)x^2
 * x= 4.7 m
 * KE= SPE
 * KE= .5kx^2
 * KE=.5(40)(.3)^2
 * KE= 1.8 J


 * What do you think Now?**


 * How does the roller coaster today get up to it's highest point
 * It gets up using cables, electricity and a motor that moves the gears.
 * Does it cost more to lift a roller-coaster full of people?
 * Yes, this is because the more people, the more weight is put on the things lifting the roller-coaster. As seen in our investigation, when we added mass to the pop-up toy, it's height kept dropping. This shows that mass affects it and you need more energy in order to lift it. The more weight added to something, the more WORK is needed to lift it and therefore it costs more.

Chapter 4 Section 4

 * What do you Think?**


 * Does gravity have a direction?
 * Yes, Gravity's direction is towards the earth
 * How can people in Australia be held on Earth when they are "upside down"
 * Gravity acts towards the earth, so it is holding the Australians down


 * Physics Talk**
 * gravitational field : the gravitational influence in the space around a massive object
 * **Earth of the source of its gravitational field because it is the first object that sets up in the space around it **
 * **Inverse-Square Relationship **
 * **acceleration due to gravity becomes less as an object moves further from the surface of Earth **
 * inverse-square relationship**:** the relationship between the magnitude of a gravitational force and the distance from the mass. this also describes how electrostatic forces depend on the distance from an electrical charge
 * Newton's law of universal gravitation: all bodies with mass attract all other bodies with mass; the force is proportional to the product of the two masses and gets stronger as either mass gets larger; the force decreases as the square of the distances between the two bogies increases


 * Checking Up **

**1. What is the direction of gravitational field in your classroom ** 2. Using the idea of field lines, where is the gravitational field the strongest > 3. If you triple the distance between two masses, what happens to their force of gravity? 4. What is the force the keeps moon in orbit around the earth? 5. What is the shape of orbit of planets around the sun?
 * Towards the ground
 * The gravitational field is the strongest near the surface of Earth because the closer you get to the earths center, the stronger gravity is
 * 1/9
 * Gravity
 * Ellipse


 * Physics To Go **

2. A satellite is sitting on a launch pad on earth 6. Astronauts on many shuttle flights study the affects of free fall by swimming in circles. "Free Fall" mimics what you would feel like if gravity were not present
 * 1. ** The gravitational force between two asteroids is 500 N. What would the ** force be if the distance between them doubled? **
 * **125 N. **
 * 2a. How would the G-Force have changed between them after launch... **
 * ** It would be 1/4 of original. **
 * 2b. What would the G-Force be if the satellite was three earth radii? **
 * ** It would be 1/9 of the original. **
 * 2c. What would it be if it was fourth earth radii? **
 * ** It would be 1/16 the original. **
 * 3. Why does everyone trust Gravity? **
 * ** Because everything so far has been going well with gravity. It keeps everything down and not floating randomly in the air. **
 * 4. Compare the acceleration due to gravity at the top and bottom of a roller-coaster. **
 * There is more gravity at the bottom, but it is so insignificant, it is negligible
 * 5a. Which is closer to the moon - the middle of the earth or the water on the side of the earth facing the moon **
 * ** The water on the side of the earth **
 * 5b. Suggest an explanation for high tides on the side of the earth facing the moon? **
 * We have high tides because the gravitational pull of the moon to where it is facing causes the water to rise higher (more attraction)
 * 5c. Use answer for A. to propose an explanation for the uneven distribution of water on the Earth's surface, as shown in the diagram **
 * ** There is an an uneven distribution of water on Earth's surface because there is land on the other parts. Also, there is different water level in different places so there is a different effect from the moons gravitational pull **
 * 6a. How would a fishes life be different without gravity **
 * ** It would stay in the water because water stays together and it's on the earth **
 * 6b. Does gravity hold a fish "down" on earth? **
 * ** Yes, because since the fish weighs very little and the earth weighs a lot, it is "attracted" to the earth. **
 *  7. Two objects have a tiny or measurable G-Force of attraction between them. How will that change if the distance is doubled, tripled, quadrupled, and halved? **
 * **a. 1/4 **
 * **b. 1/9 **
 * **c. 1/16 **
 * **d. 4x **
 *  8. How will that force change if mass of ONE of the objects is ****doubled, tripled, quadrupled, and halved? **
 * **a. 2x **
 * **b. 3x **
 * **<span style="font: 13px/19px Arial; margin: 0px;">c. 4x **
 * **<span style="font: 13px/19px Arial; margin: 0px;">d. 1/2x **
 * <span style="font: 13px/19px Arial; margin: 0px;"> 9. How will the force change if BOTH objects masses are ****<span style="font: 13px/19px Arial; margin: 0px;">doubled, tripled, quadrupled, and halved? **
 * **<span style="font: 13px/19px Arial; margin: 0px;">a. 4x **
 * **<span style="font: 13px/19px Arial; margin: 0px;">b. 9x **
 * **<span style="font: 13px/19px Arial; margin: 0px;">c. 16x **
 * **<span style="font: 13px/19px Arial; margin: 0px;">d. 1/16x **
 * <span style="font: 13px/19px Arial; margin: 0px;"> 10. How will that force change if following changes occur... **
 * **<span style="font: 13px/19px Arial; margin: 0px;">a. 2x **
 * **<span style="font: 13px/19px Arial; margin: 0px;">b. 9x **
 * **<span style="font: 13px/19px Arial; margin: 0px;">c. 6x **


 * What do you Think Now?**

1. Does gravity have a direction? 2. How can people in Australia be held down if their upside down?
 * Yes, towards the center of the earth ("down")
 * Since the direction of gravity is towards the earth, they are able to be held on earth

Chapter 4 Section 5
What do you See
 * Weighing something

What do you Think
 * Can you use the same scale to weigh a canary and an elephant
 * No the units of a canary and an elephant are way different, you will need a scale that measures grams and tons
 * How does a bathroom scale work
 * you step on it and it measures the affect gravity has on you


 * Physics Talk**


 * There is a linear relationship between the amount of force required for each stretch of the spring


 * Stretch of spring is directly proportional to the force applied to it
 * Hooke's law: the restoring force exerted by a spring is directly proportional to the distance of stretch or compression of the spring force exerted by the spring
 * F = kx
 * k is an indication of how easy or difficult it is to stretch/compress a spring
 * a stiff spring will have a large value for k; a soft spring will have a small value for k
 * weight = mg
 * force = ma
 * weight: the force exerted on a mass as a result of gravity; the weight force on an object due to Earth is downward, in the vertical direction

1. A spring obeys Hooke's Law. If the force on the spring is increased 5 times, how much does the stretch of the spring increase? 2. What is meant by the spring constant of a spring? 3. How does the weight of an object in newtons compare to its mass in kilograms? 4. When you stand on a bathroom scale, how does the force of compression of the spring compare to your weight?
 * Checking Up**
 * five times as well
 * the level of difficulty to stretch a spring
 * N = Kg x m/s^2, The mass is a part of the weight.
 * the more you weigh, the more compression of the spring is required.

1 Calculate the weight of these objects a. football player with a mass of 100 kg b. a toddler with a mass of 10 kg c. an adult with a mass of 60 kg 2. Write down the approximate weights of the following objects a. a 130 lb. student b. a 1000 lb roller coaster c. a 50 lb. child 3a and 3b. 3c. Find the slope of the graph 3d. What is the meaning of the slope? 3e. The second spring would be looser and have a less steep slope, which means hold less weight 4. A weight of 12N causes a spring to stretch 3.0 cm. What is the spring constant (k) of the spring? 5."as the force, so the stretch." Explain what that means 6.Two springs have constants of 10.0 N/cm and 15.0 N/cm. Which spring is more difficult to stretch? 7.Calculate the spring constant of the graph below 8. Write a brief description on how a spring scale works
 * PTG**
 * W = mg
 * W = (100)(9.8)
 * W = 980 N
 * W = mg
 * W = 10(9.8)
 * W = 98 N
 * W = mg
 * W = 60(9.8)
 * W = 588 N
 * .25 / 130 = 1 / x
 * x = 520 N
 * .25 / 1000 = 1 / x
 * x = 4000 N
 * .25 / 50 = 1 / x
 * x = 200 N
 * slope = 0.1491 N/(cm) = *14.91 N/m*
 * equal the spring constant
 * F = -kx
 * 12 N = k (.03m)
 * k = 400 N/m
 * Hooke wrote this because the stretch of a spring is directly proportional to the force pulling or pushing on the spring. In more detail, the more you stretch it, the more force needed to restore it
 * 15 N/cm spring
 * F = kx
 * 3N = k(.02m)
 * k = 150 N/m
 * The stretch of the spring is directly proportional to the force pulling/pushing on the spring. When at rest, the spring exerts a restoring force equal in magnitude to the force stretching or compressing the spring.