Chapter+4

toc =Section 1=

What Do You See?
4/13/2011 A guy is getting pushed in zig zags in a rolly chair, thinking he's on a roller coaster.

What Do You Think?
4/13/2011 The part where the roller coaster rides up then goes down at a high velocity produces the loudest screams. You're gradually going up then suddenly dropping and gaining velocity.

Part A
4/13/2011

Part B
4/26/2011 1a.The person pushing needs to be wary of how fast and where they're pushing the person sitting. The person sitting should also wear some type of safety equipment in case of an accident where something goes wrong, ie: falling off the chair. 3a. Rated it a 17. Going fast, making quick stops, spinning around, sharp turns, and the person sitting was laughing the whole time. Going slow, sitter rated it a 2 4a. Velocity was definitely a huge factor in the sitter's response. The bigger the change in velocity was over a shorter period of time, the more thrill it caused. Sharp turns, stopping quickly, etc. all cause the sitter to react better. 5a. 1.5 - 1.1 = 0.4m/s. 6a. 1.3 m/s east and 1.3 m/s south. The hypotenuse is the vector of the change in velocity, or acceleration. 7a. The two different speeds will form the base and height of the triangle. 7b. Yes, the change in velocity, or acceleration is responsible for the rider's reaction.

Physics Talk
4/26/2011 average velocity= displacement/ time elapsed
 * Scalar**- a quantity that has magnitude (size/amount), but no direction
 * Displacement**- the difference in position between a final position and an initial position; it depends only on the endpoints, not the path; displacement is a vector quantity, it has magnitude (size) and direction
 * Vector**- a quantity that has both magnitude (size/amount) and direction
 * Speed**- distance traveled divided by the time elapsed; speed is a scalar quantity, it has no direction
 * Velocity**- displacement divided by the time elapsed; velocity is a vector quantity, it has magnitude (size) and direction
 * Acceleration-** the change in velocity divided by the time elapsed; acceleration is a vector quanity, it has magnitude (size) and direction

Checking Up
4/26/2011 1. Displacement is a measured distance with a direction 2. 2 km 3. Velocity has a direction 4. A = change in velocity / time

Physics To Go
4/26/2011 2. The swing into the horizontal curve because it is the biggest change of acceleration 3a. Norway 3b. 1666.6 3c. The thrill comes from accelerating 4. 4m/s^2 5a. Speed 4b. Displacement 5c. Acceleration 5d. Velocity 5e. Displacement 6. 5 cm/s 7. 10 s

=Section 2=

Physics Talk
4/28/2011
 * Gravitational potential energy:** the energy a body possess as a result of its position in a gravitational field
 * Kinetic energy:** the energy an object possesses because of its speed
 * Joule:** the SI unit for all forms of energy; equivalent units for the
 * Mechanical energy:** the sum of kinetic energy and potential energy

Checking Up
4/28/2011 1. If the incline was steeper the ball will roll faster 2. If the mass increases then the height decreases and if the heigh increases then the mass increases 3. If the speed increases the mass decreases and if the mass increases then then speed deacreases 4. The GPE decreases because the height is decreasing 5. 30,000 J

Physics To Go
4/28/2011 1. The Same 2. It starts off with KE which is 1/2mv^2 and then when it goes up hills it transfers to GPE which is mgh, then converts back into KE when it goes down. 3. GPE= 60,000 KE = 0 both= 60,000 GPE = 0 KE = 60,000 both = 60,000 GPE = 30,000 KE =30,000 both = 60,000 GPE = 15,000 KE = 45,000 both= 60,000 5. GPE = 75,000 KE = 0 both 75,000 GPE= 0 KE= 75,000 both= 75,000 GPE = 37,500 KE = 37,500 both= 75,000 GPE= 15,000 KE = 60,000 both= 75,000 7a. GPE = mgh. =(.2) (10)(.75m)= 1.47 j7b. 1.47j 7c. Middle of top and bottom 8. No, because the mass cancels out in the formula 9a. B because all of the GPE converts to KE 9b. C and F 9c. D because there is more Kinetic Energy

Investigate
4/29/2011

Part A

 * Trial || Mass(kg) || h(m) || GPE (at top) || Width of ball(m) || time through gate(s) || V at bottom || KE at bottom || % difference ||
 * 1 || .226 || .063 || .1395 || .038 || .0369 || 1.0298 || .1198 || -14.12 ||
 * 2 || .226 || .147 || .3256 || .038 || .0253 || 1.5019 || .2549 || -21.71 ||
 * 3 || .226 || .229 || .5072 || .038 || .0201 || 1.8905 || .4039 || -20.37 ||
 * 4 || .226 || .312 || .6910 || .038 || .0172 || 2.2093 || .5516 || -20.17 ||
 * 5 || .226 || .397 || .8793 || .038 || .0154 || 2.4675 || .6880 || -21.76 ||

=Section 3=

Investigate
5/4/2011 Objective: Determine the launch velocity of a vertical ball launched

Theory: The launcher gives the ball KE which is converted into GPE. Assuming energy conservation: KE = GPE 1/2mv^2 = mgh 1/2 v^2 = gh vi = sqrt(2gh)

The velocity of the ball can also be measured using a photogate. A photogate method produces nearly the same result than this would validate our method. (ie: KEintial = GPE final).

The ball is launched using a spring. The SPE of the spring gives the ball KE. The KE, in turn, is converted into GPE. So: SPE -> KE -> GPE. Or simply, SPE turns into GPE.
 * Trial || Mass Of Ball (KG) || height(m) || V using energy (m/s) || Width of the Ball (m) || Time through gate (s) || V using Photogate (m/s) || % difference ||
 * 1 || 1 ball || 1 || 4.43 || 0.038m || 0.0074 || 5.14 || -13.81 ||
 * 12222 || 1 ball + 1 nickel (5g) || 0.81 || 3.98 || 0.04 || 0.0092 || 4.35 || -8.51 ||
 * 3 || 1b + 2n || 0.66 || 3.60 || 0.042 || 0.011 || 3.82 || -5.76 ||
 * 4 || 1b + 3n || 0.53 || 3.22 || 0.044 || 0.013 || 3.38 || -4.73 ||

SPE = 1/2kx^2

x = distnace the spring is compressed k = spring constant = the ratio between the restoring force and the distance the spring is stretched.

Objective: Determine the spring constant of the launcher using trial 4 x = 1.5 cm = 0.015cm h = 0.53m 1/2 kx^2 = mgh 1/2 k(0.015)^2 = (17.4grams = 0.0174kg)(9.8)(0.53) k = 803.33


 * Trial || x || m || h || k ||
 * 1 || 0.015 || 0.0024 || 1 ||  ||
 * 2 || 0.015 || 0.0074 || 0.81 ||  ||
 * 3 || 0.015 || 0.0124 || 0.66 ||  ||
 * 4 || 0.015 || 0.0174 || 0.53 || 803.33 ||

=Section 4=

What Do You See?
5/6/2011 There is a roller coaster on the moon, and the people look extremely bored. On Jupiter, however, the two people are having much more fun.

What Do You Think?
5/6/2011 The gravity on earth always points towards the center. Australia may be on the other side of the world, but it is still affected by the gravitational pull, pulling it towards the center of the earth.

Physics Talk
5/6/2011
 * Gravitational field:** the gravitational influence in the space around a massive object
 * 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 bodies increases
 * Gravity:** the force of attraction between two bodies due to their mass

Checking Up
5/6/2011 1. Center of the earth 2. When the field lines are closer together 3. It would become weaker and become 1/9th 4. 10 5. Oval

=Physics To Go= 5/9/2011 1. The force would be reduced by 125 N. 2a. The gravitational force would be 1/4 of the original 2b. The gravitational force would be 1/9 of the original 2c. The gravitational force would be 1/16 of the original 3. Everyone trusts in gravity because it's a constant force. 4. The acceleration due to gravity is the same throughout. 5a. The water side of the earth is closer to the moon 5b. The force of attraction between the two objects causes the high tides to occur on the side facing the moon. 5c. The attraction attracts the water to the side of the earth 6a. A fish would just constantly swim in circles 6b. Gravity holds the fish towards the center. 7a. 1/4 7b. 1/9 7c. 1/16 7d. 4x Greater 8a. Doubled 8b.Tripled 8c. Quadrupled 8d. Halved 9a. 4x 9b. 9x 9c. 16x 9d. 1/4. 10.
 * Mass 1 || Mass 2 || Force of Attraction ||
 * Same || Double || Twice ||
 * Double || Triple || 6x Greater ||
 * Triple || Triple || 9x Greater ||

=Section 5=

What Do You See?
5/11/2011 There's a butcher selling meat and weighing it. The butcher is weighing the same object uses different scales.

What Do You Think?
5/11/2011 No, different scales are needed for different masses. A bathroom scale works by measuring the amount of force exerted onto it.

Part A:
5/12/2011 1a. A pound if a unit of measurement 1b. Yes, because a pound is mass times gravity 1c. Force exerted by gravity

2a. 40 (9.8) = 392N 110 (9.8) = 1,078N Contrast: 1,078 - 392 = 686N

3a. 40(1.6) = 64N 110(1.6) = 176N 176 - 64 = 112N

4a. 11/2.2 = 5kg 5kg(9.8) = 49N 4b. 1/4/2.2 = 0.114 9.8(0.114) = 1.114

5a. 6,681.8

Part B:
5/12/2011 2a. The paper spring goes back inwards 3a. The paper spring decompresses 4a. No, the paper spring does not really return to its original form 6a. 7c. We predict that 120 grams will stretch 48 cm 8a. Our prediction was pretty accurate, only off by 4 cm 9a. This spring is much bigger 9b. The stretch of the second spring was less than the stretch of the first spring 9c. The steeper the slope, the more the spring stretches 10b. The springs we graphed are thicker 11. FOURTH COLUMN 11b. The greater the weight and the stretch of the spring, the greater the value in the fourth column.
 * Mass || Weight || Stretch of Spring ||  ||
 * 20 g || 1.96 N || 13 cm ||  ||
 * 50 g || 4.9 N || 21 cm ||  ||
 * 100 g || 9.8 N || 35 cm ||  ||
 * 170g || 16.66 N || 55 cm ||  ||
 * 70 g || 6.66 N || 29 cm ||  ||
 * 120 g || 11.76 N || 44 cm ||  ||
 * Mass || Weight || Stretch of Spring || NUMBER 11 ||
 * 20 g || 0.196N || 6.5 cm || 0.03 ||
 * 50 g || 0.49N || 9 cm || 0.054 ||
 * 100 g || 0.98N || 12 cm || 0.08 ||
 * 170g || 1.666N || 18 cm || 0.093 ||
 * 70 g || 0.666N || 10 cm || 0.066 ||
 * 120 g || 1.176N || 14 cm || 0.084 ||

Part C:
5/13/2011 2a. 3a.Unknown weight 1 - weight is 0.26 N. Actual mass is 25 grams. Actual weight calculated is supposed to be 0.245 Unknown weight 2 - weight is 0.41. Actual mass is 40 grams, actual weight is supposed to be 0.392.
 * Mass || Weight ||
 * 20g || 0.196N ||
 * 50g || 0.49N ||
 * 100g || 0.98N ||

Physics To Go
5/13/2011 1a. 980N 1b. 98N 1c. 588N

2a. 520 N 2b. 4000 N 2c. 200 N

3. The slope means how much the spring stretched compared to the weight, or the spring constant.



4. 12/3 = 4N/CM

5. The more force there is on a spring, the more the spring stretches.

6. 15N/cm is harder to stretch than the 10 N/CM

7. 3/2 = 1.5 N/CM

Weight = mass X 9.8m/s^2 mass is in kg weight is in newtons 1kg = 2.2 pounds

my weight in lbs is 147 lbs my mass in kg = 66.818 my weight in newtons is = 654.8164N

1.00 lb = 4.45N ("exact")

=Section 6=

What Do You See?
5/16/2011 There are two people looking at their masses going up and down elevators

What Do You Think?
5/16/2011 Yes, your weight changes, but not your mass. The scale would also change its readings because the scale reads the amount of force exerted on a certain point.

Investigate
5/17/2011

Part A:
1a. 5N 2a. 3a. 5N 4a.
 * || Acceleration (up, down, zero) || Scale Reading (larger, smaller, equal) ||
 * Mass at Rest || zero || equal ||
 * Mass up at constant speed || zero || equal ||
 * Mass accelerating upward || up || larger ||
 * Mass at rest at top || zero || equal ||
 * Mass moving down at constant speed || zero || equal ||
 * Mass accelerating downward || down || smaller ||

5a. Yes, because the weight is pulling it downwards. 5b. Yes, because the spring is keeping the weight up 5c. No 5d. Yes, they are equal because there is no acceleration

6a. There is no unbalanced force disturbing the weight, so the velocity is constant. And newton's second law states that there must be a net force acting on the object.

Part B:
1a. The scale read a larger weight when accelerating upwards, and a smaller weight when accelerating downwards 1b. Acceleration is negative when it goes downwards, therefore the weight is less. Acceleration is positive when going upwards, therefore the weight is more.

2a. Yes 2b. Yes 2c. Hand holding the spring 2d. The length of the vectors is the same.

4a. Your apparent weight would be greater in an elevator going up

5a. The apparent weight would shoot downwards at first, then level to the original weight 5b. Same as 5a.

6a. Weight doesn't change. 6c. Weight would be lower 6d. Yes

7a. Literally the same as Part A.

8a. Both accelerate up and down. Apparent weight changes on both. Roller coasters move in different direction, as opposed to just up and down.

9a. Both would hit the ground at the same time because there is the same amount of acceleration on both objects. 9b. The baseball would drop first because there is less air resistance. Yes, if you taped the crap out of it. 9c. If friction is ignored, then all objects would theoretically drop at the same time.

Physics Talk
5/19/2011 Using Newton's first law the object is at rest and no net force acts on it. Using Newton's second law the object is at rest and has zero acceleration, so no net is acting on it. Fnet=ma. Fw=mg where g=9.8N/kg

Physics To Go
5/19/2011 1a. 19.6 1b. 49 1c. 98 2a. 3.2 m 2b. 8m 2c. 16 m 3a. no because the lengths are not equal 3b. no 3c. yes 4. (up, down, zero) || scale reading (larger, smaller, equal to weight) || on top floor || zero || equal || moving down || down || smaller || down at constant speed || zero || zero || rest at bottom floor || up || smaller || at bottom floor || zero || zero || move up || up || larger || at constant speed || zero || zero || rest on top floor || down || smaller || top floor || zero || equal || 5. Elevator is moving down 6. it will be larger 7a. decrease 8a. 490 8b. 590 8c. 490 9. when the elevator is accelerating up, the scale reading up higher and when the elevator is accelerating down, the scale reading is smaller
 * || acceleration
 * a. elevator at rest
 * b. elevator starts
 * c. elevator moves
 * d. elevator comes to
 * e. elevator is at rest
 * f. elevator begins to
 * g. elevator moves up
 * h. elevator comes to
 * I. elevator at rest on

=Proposal= Name: Theme:

=Section 7=

What Do You See?
5/23/2011 People riding an unstable roller coaster, about to fall off.

What Do You Think?
5/23/2011 Because there are straps keeping the roller coaster in.

Part B:
5/24/2011 1a. The faster the string, the more force you apply 1b. More force = faster string 2a. More force needed to spin more plug things 2b. To be more consistent, and to compare forces better 2c. More mass = more force required 3a. The length of the string requires more force 3b. Must keep the force constant 4b. More force is required at the bottom 5a. Higher the speed, more the force 5b. More mass = more force 5c. The longer the radius, the more the force 5d. Make the drops bigger 6a. Very large because the faster the speed, the more the force 6b. Very small because there is barely any force from the coaster 9a. Yes 9b. yes 9c. Yes, because it has to be in order to sustain the roller coaster 11a. Very large because there is a lot of force exerted when the coaster is traveling at an extreme speed 11b. The lesser the speed, the lesser the force is required to sustain the coaster in a vertical loop, and vice-versa.

Physics Talk
5/25/2011
 * Normal force:** the force acting perpendicular to the surface
 * Centripetal force:** any force directed toward the center that causes an object to follow a circular path at a constant speed
 * Centripetal acceleration:** the acceleration directed toward the center of a circle experienced by an object traveling in a circular path at constant speed

Checking Up
5/25/2011 1. Centripetal force is required to make an object move in a circle 2. Yes, there will be centripetal acceleration 3. The track and gravity 4. Normal force 5. The mass, curve, and radius determines the amount of force that is needed

Physics To Go
5/26/2011 1a. Circle 1b. The car would be straight from its relative position 2a. The force of friction 2b. The car would go straight from its relative position just like in 1b. 3. There is more force in a faster twirl, so more force is needed to sustain the twirl. 4. Difficult because there is more weight and less friction. 5. m = mass, v = velocity, r = radius 6a. No 6b. Yes 6c. The change of velocity is the hypotenuse of the triangle 8. Blue is gravity, black is force on track, and red is the track. 9. Centripetal force adds up only the forces on the object going around in a circular motion. 11. Feel the heaviest going up against gravity 12. The roller coaster can be slow enough to not exert too much force. 13a. Heavy 13b. Light 13c. Light 13d. Light 13e. Light

=Section 8=

What Do You See?
5/31/2011 People pushing a roller coaster up hill, then the roller coaster accelerating downwards with no other forces acting upon it besides gravity

What Do You Think?
5/31/2011 Yes it takes more energy to go up a steep incline. It is more difficult to walk up a steep incline because there is more gravitational force acting against you.

Investigate
5/31/2011

Calculations
> W = 0.2 * 1.2 = 0.24J > GPE = 0.5kg(9.8)*1.5 = 7.35J > 7.35 – 0.24/7.35 = 97% > W = (77.3)*9.8*1.19 = 901.47 J > P = 901.47/6.3 = 143.09
 * 1) Part A: Calculate the amount of work done by using the work equation W = F x d.
 * 1) Part A: Calculate the gravitational potential energy, GPE = mgh, using g = 9.8 m/s2.
 * 1) Part A: Calculate the Percent Error between the Work and GPE for each trial.
 * 1) Part B: Calculate the amount of work done by using the LCE, W = GPE.
 * 1) Part B: Compute the power, in watts, that you generated up the stairs. P= W/t

Analysis
> The work done is completely off compared to the amount of GPE at the top of the incline. The lesser the distance, however, the lesser the % difference.
 * 1) Compare the amount of work done to pull the cart up the incline to the amount of GPE at the top of the incline for each trial.

> The force less
 * 1) How did the force required change as the distance to reach the height increased?

> The amount of work was the same for every type of motion.
 * 1) Compare the amount of work done to move up the stairs in each type of motion.

> The power increased
 * 1) How did the power required change as the time to reach the height decreased?

> The amount of force applied to the cart, and the amount of time the force is applied can mess up the experiment. For example, if a person pulls the cart up on a slant and not parallel to the ramp and accelerate the cart, the readings will be off.
 * 1) Hypothesize as to possible reasons why the results might not come out as expected. Be specific, and do not list mistakes… only experimental errors. Explain how the errors actually could affect the data.

Physics Talk
5/31/2011 w=fd p=work/delta t
 * Work:** the prodct of displacement and the force in the direction of the displacement; the energy transferred to an object
 * Power:** the work done divided by the time ekaosed the speed at which work is done and energy is transferred
 * Watts:** the SI unit for power; 1W=1j/s

Checking Up
5/31/2011 1. The energy turns into GPE 2. the work and gravity 3. there is less force to gradually lift it than to lift it straight up 4. the brakes convert KE to thermal energy 5. J/s

Physics To Go
5/31/2011 1a. There is more GPE on top 1b. 9.8 1c. the same 1e. GPE to KE to SPE 1f. when it hits the spring 2a. 1050 2b. 30 2c. 2000 2d. 350 3. transfer energy 4. the mass 5a. 200,000 5b. 10000

=Final Review= 6/6/2011



=Chapter Challenge: Paper Roller Coaster Proposal= Great Adventure! My associate and I have a proposition for you. Our roller coaster that we have currently built successfully achieves all of the thrills and chills people oh so desire. We will list the specifications and model diagram for you, so please read thoroughly.

Newton's second law states that the heavier an object is, the more force is required to move it. That is precisely why our ride starts at such a high height; because the higher the height of an object is, the more Gravitational Potential Energy the object has, and through energy conservation, conserves most of its energy throughout the entire ride. The coaster accelerates downhill from its starting peak, due to gravitation pulling the object down towards the center of the earth. The apparent weight of the ride and its riders, increase as there is more force exerted on their bodies, ie: before approaching loops, or going downhill. Power is defined as force over time, and the faster that the coaster goes, the more power it has. The work done is always the same, however, the power differs depending on the amount of time elapsed. Our coaster, we ensure, provides an exciting amount of power due to the speed of the coaster. At the end of the ride, there is a "spring" that consists of a ball, which, by hooke's law, states that the ball will compress and slow down the ride. It is not really needed, however, safety is our primary concern.

Measurements: 90 CM tall 56 CM before first loop 4 CM radius on first loop 38 CM before turn 13 CM radius of turn 9 CM before camel hump 27 CM before horizontal loop 6 CM radius on horizontal loop 15 CM after horizontal loop 4 CM radius of ball

Our rides safety is immaculate. There is not a single fault in our safety specifications. The roller coaster stops at just the right amount of speed as to avoid any hard collision with our second safety net, the ball. The velocity of the coaster right before the impact of the ball is almost 0. This design is perfect: it has just the right amount of speed at the end, and throughout the entire ride, the coaster remains on the tracks. There is not a single safety flaw in our design.

Once again, our roller coaster's safety is immaculate. The coaster always functions as planned, and never causes any problems. Consider our design, for it is impeccable. Thank you for your time, and I guarantee that your customers will be happy if our design is chosen.