Chapter+2+Section+1-5

= **Jason Mironidis CP Physics Wikilog - Ms. Burns- 2010** =

= = toc

**Chapter 2, Section 1:**

 * Science Reference in Sports (11/7/10) **

media type="file" key="Sport Science- The physics of hitting a baseball- Hit the ball square with the ImpactBat.MP4" width="300" height="300"


 * In the video above it talks about hitting a baseball and the many factors that are in play. Many things can be altered when hitting the ball. Such as the ball's speed, the bat's speed, the players bat angle, the players stance, (etc.) The main reference to science in this video was about momentum, which is mass multiplied by velocity. The way they describe it in the video is, a baseball bat with more mass and speed given by the swinger, will provide more momentum; thus, sending the ball farther, as opposed to a faster pitch, when trying to hit a home run.


 * Source: []
 * Quote: "momentum, which is a product of mass and velocity. A bat has more then 6x more momentum then a baseball which is why the swing speed is much more important then the pitch speed in the home run equation."


 * What do you See? (11/8/10) **
 * Many different people and animals moving a ball
 * Some are kicking it very far, other barely at all
 * Some are moving very fast and some not at all


 * What do you think? (11/8/10) **
 * How do figure skaters keep moving across the ice at high speeds for long time without seeming to use effort
 * At first, the skater needs to speed up and put a lot of energy, then, due to the very low friction and momentum gained previously, the skater can move with little effort


 * Why does a soccer ball keep rolling on the field after being kicked?
 * Because the initial kick from the player gives enough momentum to the ball to keep going until friction stops it


 * Physics Talk (11/8/10) **


 * Inertia - the natural tendency of an object to remain at rest or to remain moving with constant speed in a straight line
 * a property of matter
 * measures the resistance to changes in motion


 * Mass- the measure of an objects inertia
 * Weight- how much gravity pulls on a mass 65
 * Force - a push or pull
 * Objects never stop on their own, but there is a frictional force that cannot be seen that stop them
 * Newton's First Law of Motion: In the absence of an unbalanced force, an object at rest remains at rest; and an object in motion remains in motion with constant speed in a straight line path
 * An objects mass is a measure of its inertia, the greater the mass, the great the inertia
 * SPEED IS NOT IMPORTANT


 * Speed of an object is equal to the sum of the speeds contributing to its speed


 * Checking Up (11/8/10) **


 * What is inertia?
 * the natural tendency of an object to remain at rest or to remain moving with constant speed in a straight line


 * Describe Newton's First Law of Motion.
 * In the absence of an unbalanced force, an object at rest remains at rest; and an object in motion remains in motion with constant speed in a straight line path


 * What needs to act on an object to stop it moving?
 * A force


 * What stops the motion of the ball?
 * Friction


 * Which mass will have a greater inertia?
 * The one with the greater mass


 * Why is it important to establish a frame of reference?
 * Because you have to take into account the speeds from both forces


 * Physics To Go **

1. You push a ball to start rolling along a perfectly frictionless surface...
 * How far will the ball roll?
 * It won't stop moving


 * Explain your answer using newtons first law of motion
 * According to Newton an object in motion with constant speed will remain there in the absence of an unbalanced force, since there is no friction (the force), the ball will keep rolling

2. A ball is released from a vertical height of 20 cm, where will it end up on the second ramp before traveling back down? 3. Can an object in the real world move at a constant speed forever? 4. Describe the motion of a hockey puck 5. Riding a bike with brother 6. Track and Field Athlete 7. Train and Car
 * 20 cm
 * No because there will always be friction no matter how little or how much to stop the object
 * The puck is traveling at a constant speed because of inertia and nothing has bothered it so it keeps going like newtons first law said, oh no! there's something in the way and now it stopped
 * 7 m/s
 * 14.5 m/s
 * What is the velocity of the cart relative to the ground when the cart is moving toward the front of the car?
 * 8 m/s forward


 * What is the velocity of the cart relative to the tracks when moving toward the rear of the car?
 * 3.2 m/s forward


 * What is carts velocity relative to the ground when cart is being pushed perpendicularly?
 * 6.1 m/s @ 23 degrees from trains direction

8. Horse and Arrow 9. Ball and Ramp
 * 67 m/s
 * 45 degrees

**Chapter 1, Section 2:**

 * What do you See? (11/10/10) **


 * The person on the top picture seems like he has nothing to do so he is slowly and casually walking
 * In the second picture he is rushing to his love interest and is going very fast
 * You can see the difference in their speeds through their footsteps and the exaggerated wind on the second picture


 * What do you Think? (11/10/10) **


 * The meaning of 100 mi/h or 45 m/s means that in an hour, if the ball was able to go constantly at that speed, the ball would reach 100 miles. and 45 meters in a second.


 * Physics Talk (11/11/10) **


 * Positive Acceleration- the dots got farther apart as time went on
 * Negative Acceleration- the dots got closer together as time went on
 * Constant Speed- The dots stayed the same distance as time went on


 * Checking Up (11/11/10) **

1. Describe the pattern of dots on a ticker tape for each of the following situations
 * a. Constant speed
 * Dots stay the same distance apart from each other


 * b. positive acceleration
 * the dots start closer together and spread apart


 * c. negative acceleration
 * the dots start farther apart and end up closer together

2. An athlete runs 400 m in 50 s. What is the runner's average speed 3. What is the difference between instantaneous speed and average speed 4. A vehicle accelerates from 0 km/h to 100 km/h in 10s. What is its average acceleration?
 * 8 m/s
 * Instantaneous speed is the speed right away and average is the speed throughout a course of time
 * 10 m/s squared


 * Physics To Go (11/13/10) **

1. In your own words compare average speed and instantaneous speed 2. Calculate the average speed in each of the following situations 3. In which of the following cases is acceleration occurring? Indicate positive or negative 4. Which graph represents what happens 6. A vehicle traveling at 45 km/h comes to a stop in 9s
 * Average speed is the sum and division of all speeds. It means that all the speeds you go are close together and come to one number
 * Instantaneous Speed is instant speed right when you start accelerating
 * A horse runs 1km in 15s: 66.67 m/s
 * A skier travels 84m in 6s: 14 m/s
 * You walk 9.6 km in 2h: 4.8 km/h
 * A car travels 400km in 4.5 hrs: 88.89 km/h
 * A runner falls down: Negative
 * A runner takes off from a starting block: Positive
 * You walk down a straight hall at a steady speed: None
 * A soccer ball is caught by a goalie: Negative
 * A bowling ball at a constant speed: None
 * A parachutist falls at a constant speed: None
 * Student moving with a constant increase in speed: A
 * Student moving with a constant speed: B
 * Greatest change in speed/second: C
 * Speed Increase then decrease: C
 * Positive, Constant, Positive then Negative, Positive
 * How fast did the vehicle accelerate?
 * -5 m/s squared


 * Does the acceleration have a positive or a negative value?
 * negative

7. Describe the motion that made each of the following ticker tapes 8. A family drives 100 mi in 2 hrs. What is their average speed 9. A person drives to work at an average speed of 15 m/s Does this mean that the persons instantaneous speed was always 15 m/s? Explain. 10. A sprinter starts from rest and then accelerates to her top speed. If she were pulling on a ticker tape, sketch what the tape might look like. 11. A sports car accelerates at 4 m/s every second. Calculate the speed of the car after each of the first 5s 14. Describe situations in sport that can produce ticker tapes patterns similar
 * Tape 1: Constant
 * Tape 2: Constant then Positive Acceleration
 * Tape 3: Constant, then Positive Acceleration, then Negative Acceleration, then constant
 * Tape 4: Constant, Negative, Constant, Positive
 * 50 mi/h
 * Not necessarily, it just means that all his speeds added and then divided = 15 m/s. He is traveling around 15 m/s not always
 * (see work)
 * 4, 8, 12, 16, 20 m/s
 * Constant motion at average speed: NYC Marathon
 * Constant motion at fast speed: Ussain Bolt breaking the 100m record
 * Constant motion at slow speed: A basketball PG bringing the ball up the court after inbounding it
 * Positive Acceleration: Chris Johnson (RB) picking up speed running down the field trying to score a touchdown
 * Negative Acceleration: Drag Racing cars trying to slow down after the race is over

Work Shown


 * Physics Plus (11/16/10) **

**Chapter 2 Section 3**

 * What do you See? (11/16/10) **
 * The kid is pushing the ball
 * As the ball is getting faster he has to as well
 * The dog is having a hard time keeping pace with him

** What do you Think? (11/16/10) **

What is a force? How will the same amount of force affect a tennis ball and a bowling ball differently
 * a push or pull
 * The tennis ball will go farther then the bowling ball because it weighs less and the force will work on it more


 * Physics To Go (11/16/10) **


 * Newtons Second Law of Motion
 * If there is acceleration, there must be an unbalanced force acting upon it
 * Newtons Second Law of Motion formula
 * Acceleration = Force/Mass (a=f/m)
 * Weight- The force of gravity acting on an object and the acceleration due to gravity
 * Free Body Diagram- used to show relative size and direction of all forces acting on an object

Checking Up (11/16/10)

1. Describe Newton's second law of motion in your own words 2. For a constant force, what effect does increasing an object's mass have on its acceleration? 3. An object weighs 20 N. How would you explain this statement according to what you know about mass and acceleration due to gravity? 4. If you went to a planet with a higher acceleration due to gravity, what would happen to your weight? What would happen to your mass?
 * If there is acceleration, there must be a force acting on it
 * It will slow down
 * The objects weight is determined by the force/acceleration.
 * They would both decrease


 * Physics To Go (11/18/10) **

1. Calculate the Missing Values

3. What is the acceleration of a .30 kg volleyball when a player uses a force of 42 N to spike that ball?
 * 1. 350N
 * 2. 80 kg
 * 3. 10 m/s squared
 * 4. 80 kg
 * 5. -15 m/s squared
 * 6. -3000 N

4. What force would be needed to accelerate a .040 kg golf ball at 20.0 m/s squared 5. Explain situations in terms of 9. You throw a ball. Is the force of your hand still acting on the ball? When does it stop 10. Carlo and Sara push on a desk in the same direction. Sara pushes with force of 50 N, and Carlos with a force of 40 N. What is the unbalanced force acting on the desk? 11. A vehicle is stuck in the mud. Four adults each push on the back of the vehicle with a force of 200N. What is the combined force 12. A baseball player throws a ball. While the 700-g ball is in the pitchers hand there is a force of 125 N on it. What is the acceleration of the ball. 13. During a football game, one player tackles with 50.0 N to the east and the other 120 N to the north. What is the resultant force to the player being tackled? 14. In Auto-Racing, a crash occurs. The red car hits the blue car from the front with a force of 4000 N. A yellow car hits the blue car from the side with 5000 N. What is the resultant force? 15. The acceleration due to gravity at the surface of Earth is approximately 9.8 m/s squared. What force does the gravitational attraction of Earth exert on a 12.8 kg object. 16. A force of 30.0 N acts on an object. At right angles to this force, another force of 40.0 N acts on the same object 17. Bob exerts 30.0 N force to the left on a box (m = 100.0 kg). Carol exerts a 20.0 N force on the same box, perpendicular to Bob's Force 18. Write a script for a voice-over that deals with accelerated motion and forces for a sport
 * 140 m/s squared
 * .8 N
 * Newtons First Law of Motion
 * The baseball and bowling ball stay in motion until you (the force) catches them and they start moving one a force (you) throws them. Also the bowling ball has a greater mass, therefore, a greater inertia. That means it is harder to start and stop moving.
 * Newtons Second Law of Motion
 * Because the baseball weighs less then a bowling ball and the same force is used on both, the baseball will travel farther and be easier to throw
 * The force of your hand is acting the whole time the ball is moving and stops when the ball either stops or changes direction
 * 90 N
 * 800 N. The total force of created by the four adults which is 200 N each is added and gives you 800N.
 * 179 m/s squared
 * 130 N @ 67.4 degrees NE
 * 6,403 N @ 39 degrees to the side
 * 125 N
 * What is the Net force on the box?
 * 50 N @ 37 degrees towards the object
 * What acceleration would this object have if it is a 5.6 kilogram wagon?
 * 8.93 m/s squared
 * What is the net force on the box
 * 36 N @ 34 degrees towards object
 * Determine the acceleration of the box
 * .36 m/s squared
 * At what rate would the box accelerate if both forces were going east
 * .5 m/s squared
 * Welcome ladies and gentlemen to game 7 of the world series. We are here in the 9th inning 2 outs. All the Yankees have to do is get one more strike and the game is over. The baseball weighs 1 kg. CC Sabathia exerts 200 N of force on the ball. Force divided by mass gets us 200 m/s squared and CC strikes Ryan Howard out!!!! GAME OVER YANKEES WIN, YANKEES WIN

Work Shown V


 * Physics Plus (11/22/10) **

Chapter 2 Section 4: Projectile Motion: Launching things into the Air

 * What do You See? (11/23/10)**
 * Women is throwing two things to ground
 * Man seems to be timing the time it takes them to fall


 * What do you Think? (11/23/10) **


 * What determines how far an object thrown into the air travels
 * Force exerted
 * Height it is thrown
 * Amount of strength used to throw object
 * Natural Factors (Wind)


 * Physics Talk (11/23/10)**
 * Trajectory - path
 * Projectile - an object acted on ONLY by gravity
 * The x-component and y-component of all vectors are independent
 * Vertical velocity affects vertical distance (y-axis)
 * Horizontal velocity affects horizontal distance (x-axis)
 * Time for a horizontally launched projectile to hit the ground (hang time) is the same as the time it takes to drop
 * Acceleration due to gravity is -9.8 m/s sq
 * Gravity is vertical, therefore it only affects the y-axis
 * Y velocity is always 0 at maximum height
 * <span style="font-family: Arial,Helvetica,sans-serif;">Launching horizontally results in the same trajectory at the second half of the ball thrown at an angle

<span style="font-family: Arial,Helvetica,sans-serif;">1) Yes, with the acceptance of air resistance things drop at the same speed 2) No, it increased by 9.8 m/s every second 3) Velocity is 0, acceleration is -9.8 m/s sq
 * Checking Up (11/23/10)**


 * Video **

http://www.youtube.com/watch?v=wmCUBQa376w


 * In this video you see an athlete shooting a jump shot by shooting a ball. In the case of basketball, the trajectory in the case of basketball can be different. In some cases it can have a lesser angle and less force, but in others you need a higher angle and higher force. The higher the trajectory the nicer the shot looks and the better the opportunity it will go in. Of course that is to an extent. If the trajectory is too high the ball might air ball.
 * The vertical motion is affected by gravity and the horizontal motion is affected by mostly the force i put on the ball.


 * Physics To Go (11/23/10) **

1. Sketch two coins leaving the table 2. Sketch two coins leaving the table, one at faster horizontal 4. Survey your family and find out if they think a shot bullet or a dropped bullet drops first. Why would they think that? 6. "A projectile's horizontal motion has no affect on its vertical motion and vice versa." Explain this. 7. What drops first neglecting air friction from the same height, a shot arrow, or dropped arrow? 8-10. 11. Write a script about a baseball pitched and hit into the outfield
 * (see work)
 * (see work)
 * Dad: Same Time
 * Mom: Dropped Bullet
 * Brother: Dropped Bullet
 * Sister: Dropped Bullet
 * Explain: My dad is a physics major so he obviously knows that. As for the rest of my family, it would just seem logical that the bullet dropped would drop first because a shot bullet seems to travel longer and would take a longer time to drop.
 * The best way to explain this is through the example set in class with Taylor and Lucas. Vertical Motion was not affected by the speed Lucas gave to the chair, but the Horizontal Motion of the ball was. Also, when Taylor threw the ball, it did not affect its horizontal motion, only its vertical
 * They both fall at the same time because they start at the same height and gravity has the same affect on both.
 * Ladies and Gentlemen, the pitch is thrown. The ball is traveling very fast at a somewhat arched trajectory. Meanwhile the Batter has arched his body to allow both horizontal and vertical forced to be placed on the ball. The force the bat exerts on the ball sends the ball flying in a very arched trajectory. The ball is going... going... GONE. SEE YA, Yankees Win! Yankees Win!!!

Work Shown V


 * Physics Plus (11/30/10) **


 * What do You Think Now? **


 * After learning from this chapter, I believe that the velocity, mass, max height, force, and direction determine how far an object thrown into the air travels before landing. From the observations made in the investigate, I believe gravity determines how far an object travels after it is thrown as well as the things stated above.

Chapter 2 Section 5:

 * What do you See? **
 * A girl kicking a ball in the air
 * Bounces off boys head and goes into goal


 * What do you Think? **
 * Describe the various trajectories of projectiles launched from the ground at various angles
 * The object will go in a certain direction depending on the angle you send it and also descend in the same angle I believe
 * Describe how a greater launch speed of a projectile might change the range when the launched angle is the same
 * By adding a greater launch speed the projectile will travel for longer, but it will probably not change the angle in which it lands. Since you are adding more force to moving the projectile, it has to go farther then putting less force on it


 * Physics Talk (12/2/10) **
 * A projectile has two motions that act at the same time and do not affect one another
 * One motion is constant along a straight line (affected by launch speed and direction)
 * The other is downward acceleration at 9.8 m/s sq. (affected by launch)
 * Physical model: the evenly spaced strings of calculated lengths
 * Without air resistance, all trajectories are parabolas
 * Balls travel in parabolas
 * A 45 degree launch produces the greatest range (longest distance)
 * Complimentary angles travel the same distance
 * Angles smaller than 45 have greater horizontal velocities but are up for a shorter amount of time
 * Angles larger than 45 have smaller horizontal velocities but are up for longer amount of time
 * Exceptions: curve balls, temperature

** Checking Up (12/2/10) **

1. What are the two types of motion that help you understand the trajectory of the projectile 2. What is the fundamental requirement a scientist must meet when proposing a model of some natural phenomenon? 3. How does the launch vary if its launched from 10-80?
 * Constant and Downward acceleration
 * For a model to be accepted, it must match the reality in nature
 * Height and range with different angles: a 45 degree launch produces the greatest range, pairs of angles (add up to 90) are identical distances.


 * Physics To Go (12/2/10) **

1. If the launching and landing heights for a projectile are equal, what angle produces the greatest range? 2. Compared to a launch angle of 45, what happens to the amount of a time a projectile is in the air if the launch angle is... 3. For a constant speed, what angle produces the same range as a launch angle of... 4. Long jumper angle is 18 far less the 45 why is that so? 5. Why is Carl Lewis successful in both events 6. Diagram shows ball thrown toward east and upward at an angle of 30 7. A diver jumps horizontally off a cliff with an initial velocity of 5.0 m/s. The diver strikes the water 3 seconds later 8. What value of theta would result in the ball traveling the longest horizontal distance w/o air resistance? 9. Four balls, each with mass (m) and initial velocity (v), are thrown at different angles by a baseball player. Neglecting air friction, which angular direction produces the greatest projectile height? 10. The diagram shows a ball projected horizontally with an initial velocity of 20.0 m/s east, off a cliff 100m High. Work Shown
 * A 45 degree angles produces the greatest range because it evenly distributes the force vertically and horizontally
 * greater then 45
 * If it is greater then 45 the projectile will spend more time in the air have a smaller range
 * less then 45
 * won't spend as much time in the air as > 45 degree angle, but will still have a smaller range because there is not as much vertical force
 * 30 degrees - 60 degrees
 * 15 degrees - 75 degrees
 * This is because 45 degrees gives you the best range, but long jumpers aim for the best horizontal velocity, which is why they are focusing on horizontal launch (18 degrees)
 * Since Carl Lewis was very fast, he was able to use his speed in sprints and convert it to horizontal force to be able to jump well in the long jump.
 * What is the direction of the balls acceleration in point x?
 * Acceleration is downward because of gravity
 * What is the direction of the balls velocity on point x?
 * Southeast
 * What is the vertical speed of the diver upon reaching the surface of the water
 * 29.4 m/s
 * What is the horizontal speed of the diver 1.0s after the jump
 * 5 m/s
 * How far from the base of the cliff will the diver strike the water?
 * 15m
 * Closest to 45 degrees
 * The greatest projectile height would be created with a 90 degree throw. Although that would not get the ball anywhere in terms of horizontal distance, it will give it the greatest height
 * During the flight of the ball, what is the direction of its acceleration?
 * Down
 * How many seconds does the ball take to reach the ground?
 * 4.5 seconds
 * How far from the base of the cliff does the ball land?
 * 90 meters


 * What do you Think Now? (12/2/10) **


 * As an angle is increased the range increased, when the angle is 45 degrees, that is the optimal range it can reach. Complementary angles have same range for ground-to-ground launch. Max range is at 45 degrees (also only for ground-to-ground launch. The greater the speed the further it will go.


 * Physics Plus (12/3/10) **


 * Chapter Mini Challenge Possible Video: **

http://www.youtube.com/watch?v=7SLf7DIGPbg