QUICK REVIEW Semester Final Fall

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1 Keep in mind that a lot of questions on the final are conceptual and don t necessarily require an equation or numbers just a little (or a lot) of thinking. BE PREPARED ANSWERS MAY OR MAY NOT BE TO SIG-FIGS Graphing Reading Graphs What the independent variable is and where it goes on a graph. The uncontrolled variable x axis What the dependent variable is and where it goes on a graph. That which is being measured y axis Quantitative and Qualitative measurements What s the difference? Qualitative = no numbers (tall, big, wide) / Quantitaive = numbers (3 m wide, 5 m tall) SI (metric) and measurement QUICK REVIEW Semester Final Fall How to convert from one unit to another Know your prefixes and their order kilo, hecto, deca, base unit, deci, centi, milli Understand the difference between mass and weight and how to go about calculating each. w = m g What is the weight of an object that has a mass of 67 kg? 657 N What is the mass of an object that has a weight of 345 N? 35.2 kg The basic unit for each SI measurement How to convert from one unit to another kilograms decagrams centigrams milligrams 15.0 g.0150 kg 1.50 dag cg mg How to convert from SI to English or English to SI Convert using the following 1 mile = 1.61 kilometers 3.78 liters = 1 gallon 1 inch = 2.54 cm 1 kilogram = 2.2 pounds 64 miles = 103 km liters = 62.0 gallons cm = 49 inches 190 pounds = 86.2 kilograms 24.5 pounds = kg 24.5 pounds = Newtons 33.0 cm = kilometers 10.0 km = millimeters Significant Figures and Scientific Notation Review your Guidelines How many significant digits in the following: x Give the answer in the correct number of significant digits: = x = = = 6.46

2 Put the following numbers in scientific notation: = 1.23 x = 1.2 x Write the following as ordinary numbers 6.01 x x Calculate the following. Write the answer in scientific notation using the proper number of significant digits. (4.5 x x 10 5 ) = 6.7 x 10 5 (1.99 x x 10 2 ) = 1.7 x 10 0 (4.5 x x 10 4 ) = 9.9 x 10 9 (1.99 x x 10 2 ) = 1.9 x 10 3 Linear Motion The difference between a scalar and vector quantities scalar = just a magnitude 25 m/s Give an example of a scalar and a vector quantity vector = magnitude and direction 25 m/s NORTH SPEED - Review: Speed Racer How is it defined rate of change of motion and how to calculate it v = d/t Remember that speed/velocity is expressed as m/s What is the speed of an object that travels 10.0 m in 1.5 s? 6.7 m/s How long does it take an object to travel 50.0 m at a speed of 5.3 m/s? 9.4 m/s What distance does an object travel if it has a speed of 3.4 m/s for 12 s? 41 m VELOCITY How is it defined? What makes it different from speed? Velocity = speed and direction VECTORS addition of and resultants. What are the resultant vectors for the following? + = 20 N + 5 N = 15 N DISPLACEMENT How is it defined? - distance from point of origin know how to calculate displacement and direction. A bird flies directly North for 125 km, turns and flies 77 km directly South. What is its displacement? 48 km N An AA athlete begins a m race (one lap around the track) and finishes where he started 50.1seconds later. What is the displacement of the athlete just as he crosses the finish line? 0.0 m A person walks 7 km north then 2 km east. What was their displacement and direction? 7.28 km NE A bird flies 45 m north, then 16 m south, then 3.0 m back north. What distance did the bird fly? What was the bird s displacement? 64.0 m total distance / displacement = 32 km N VELOCITY VECTORS and DISPLACEMENT A boat can travel 5.0 m/s in still water. The boat attempts to cross a river that is flowing west at 8.0 m/s. The boat heads north across the river. What is the resulting velocity of the boat and the direction in which it actually travels? 9.4 m/s W of N ACCELERATION - rate of change of velocity REVIEW: Motion Accomplished How is it defined and how to calculate it and manipulate the equation. Remember that acceleration is expressed in m/s 2 What will cause acceleration? Net force A bicyclist moves from rest to 3.0 m/s in 6.0 seconds. What was the rate of acceleration?.50 m/s 2

3 If a child on a tricycle is moving at 3.0 m/s how long will it take her to reach a speed of 8.0 m/s if she accelerates at 0.50 m/s 2? 10.0 sec DISTANCE with constant acceleration d = 1 /2 a t 2 How far does the bicyclist in the above question go in the 10.0 seconds? 25.0 m FREE FALL AND GRAVITY GRAVITY at what rate does an object fall due to gravity? 9.81 m/s 2 What effect does air resistance have on falling objects? Slows them down What is terminal velocity? What is your acceleration when you reach terminal velocity? Final velocity reached when air resistance and gravity balance. At this point acceleration = 0.0 m/s 2 You drop a rock off of a bridge. What is the velocity if it falls for 8.0 seconds? 78.4 m/s How far will that rock fall in 8.05 seconds? m A person falls off of a 15.0 m platform. How long are they in the air? 1.75 s An acorn falls from a tree branch and smashes to the ground 11.0 seconds later. How fast was it moving just before it hit? 108 m/s PROJECTILES - (ALWAYS neglecting air resistance) REVIEW Plunger Cannon Activity / Target Acquired Activity What is a projectile? Any object that is thrown/tossed or moving through the air What is a trajectory? Curved (parabolic) path Why do projectiles follow a curved path? The resultant of Inertia and gravity How do the vertical and horizontal velocities of a projectile compare/differ? Are they dependent on one another? Do they affect one another? Vertical velocity changes / horizontal velocity is constant An object is thrown UP into the air. What is its acceleration? In what direction is it accelerating? at 9.81m/s 2 A ball flies off the edge of a 50.0 cm high table at a speed of 1.20 m/s. How far from the base of the table will the ball hit the ground. d =.38 m Kedge falls from a 25.0 m high roof and lands 4.00 m from the base of the building. How long was he in the air? t = 2.26 s A tennis ball leaves the edge of a table with a speed of m/s. It lands.650 m from the base of the table. How high is the table? d = 2.8 m FRICTION - REVIEW Mu of a Shoe Activity What is the Normal Force (FN)? What unit is it expressed in? force perpendicular to a surface (N) What is µ? Coefficient of linear sliding friction What is the Frictional Force (FF) What unit is it expressed in? Force needed to slide an object along at a constant rate How does friction act on an object that is being pushed or pulled? It opposes motion Make sure you understand the equation FF = µ FN and how to calculate each component. (Understand that it is often written as F = µ N) Be sure to understand the terms: Static Friction keeps objects still and unmoving Starting Friction gets objects moving and out of the static state Sliding Friction holds object back as they slide at a constant rate A box with a weight of 78.0 N rests on a concrete floor. If the coefficient of friction between the two surfaces is.450, how much force is needed to keep the box sliding at a constant rate? 35 N A box is dragged across a tile floor at a constant rate with a force of 453 N. The coefficient of friction between the box and the floor is.440. What is the weight of the box (FN)? 1030 N A 88.0 kg box can be pushed along a floor at a constant speed using a force of 78.0 N. What is the coefficient of friction (µ) between the two?.089

4 NEWTON S LAWS OF MOTION Newton s First Law of Motion What does it state? Objects at rest/in motion remain so unless acted upon by an outside force Can you give an example? Newton s Second Law of Motion What does it state? A net force causes motion in the direction of the force Can you give an example? Newton s Third Law of Motion - REVIEW Action-Reaction Activity What does it state? For every action there is an = and opposite reaction Can you give an example? INERTIA Make sure you understand not only the definition of Galileo s principle of INERTIA, but how it applies to any situation. How is INERTIA defined? What affects it? Inertia is the natural tendency for a object to resist a change in its motion it is affected only by the MASS of the object Be SURE you understand the difference between MASS and WEIGHT Mass = kg (amountof matter) / Weight is a FORCE = N (w = m g) FORCE What is it? F = m a Remember that 1 N = 1 kg m/s 2. (It s the same thing) What are the two most common types of outside forces? Friction and Gravity A constant and unchanging net force is applied to an object What can you say about the object s motion? It will undergo an accelerated motion What amount of force has to be applied to a kg object in order to accelerate is at 1.50 m/s N What is the acceleration of Kedge (82.0 kg) if he has a force of 9.00 N applied to him as he is pushed off of a cliff? 0.11 m/s 2 What is the mass of an object that was accelerated to 2.50 m/s 2 with a force of 32.0N as it was pushed at a constant rate? 12.8 kg A constant unchanging force of 3.5 N is applied to a 10.0 kg shopping cart. What is the speed of the cart after 13.0 seconds 4.5 m/s Is Weight a FORCE? Ya! Weight is a force due to gravity MOMENTUM REVIEW: It s about TIME What is momentum? A property any moving object has that includes its mass and velocity What is the proper unit for momentum? Kg m/s Make sure you understand the equation ρ = m v What is the momentum of a 67.0 kg rock rolling along at 2.00 m/s? 134 Kg m/s IMPULSE What is impulse? What is the unit for Impulse? Force applied over time N s Make sure you understand the formula Impulse = F t If a car engine provides a thrust of N, how long must it run to produce N s of impulse? 3.01 s A rocket engine produces N of force for seconds. What is the impulse applied? N s A 3.00 N force acts on a 2.00 kg object moving at 5.00 m/s for 11.0 sec. A) What is the object's change in momentum? B) What impulse acts on the object? C) What is the object's final speed? A) 33 kg m/s B) 33 N s C) 21.5 m/s Make sure you understand the equation FΔt = Δ(m v) A 234 kg frictionless cart is to be sped up from rest to 4.00 m/s. If a force of 67.0 N is applied, for how long must you push the cart? 13.9 s

5 What braking force is needed to bring a kg car going 24.0 m/s to rest in 1.00 sec N COLLISIONS - REVIEW Glide and Collide Activity What is an elastic collision? Objects bound/rebound with no lasting deformation Can you give an example of an elastic collision? Bouncing a basketball What is an inelastic collision? Objects have lasting deformation; no bound/rebound; may stick together Can you give an example of an inelastic collision? Car accident LAW OF CONSERVATION OF MOMENTUM What does the law state? Total momentum of a group of objects does not change unless external forces act Can you give an example of the law in action? The Newton s cradle; billiards.etc Make sure you understand - m1v1 (before) + m2v2 (before) = m1v1 (after) + m2v2 (after) m1v1 (before) + m2v2 (before) = m3v3 (after) for masses that COMBINE after the collision A 3.00 kg steel ball rolls along at 1.70 m/s and runs into a 2.00 kg steel ball rolling at 5.00 m/s. After the collision, the 3.00 kg ball has a speed of 1.30 m/s. What was the speed of the second ball? 5.60 m/s Find the original velocity of a 3.00 kg small fish that has been consumed by a 12.0 kg large fish moving at 3.00 m/s. The final velocity of the two fish after the big one eats the little one is m/s in the opposite direction m/s WORK and POWER - REVIEW Stair Wars Activity - W = F d P = W/t What is Work? Force applied over a distance What is the proper unit for work? Joules (J) How do you know that WORK has been done on an object? (the three rules for Work) Net force applied / object moves in the direction of the net force / energy of the object changes Using a force of 567 N, Lopez lifts a box a distance of 1.80 m. How much work has Lopez done? 1021 J A balding child, wishing for a red wagon, pulls a wooden box through the dirt a distance of 66.0 meters with a force of 38.0 N. How much work is done on the box? 2508 J What is Power? Rate at which work is done What is the proper unit for Power? Watt (W) (Joules/second) A figure skater lifts his partner, who weighs 488 N, 1.00 meter in 3.00 seconds. How much power is required? 163 W How much power does a person weighing 334 N require to carry a 16.0 N box up a 5.00 meter ladder in 5.00 seconds? 350 W ENERGY KE = 1 /2 m v 2 GPE = m g h How is energy defined? The ability to cause change or the ability to do WORK Kinetic Energy - How is it defined? Energy of Motion Potential Energy - How is it defined? Energy of position/condition What is the kinetic energy of an 82.0 kg Kedge running at 1.80 m/s?132.8 J What is the velocity of a 1.50 kg ball that has 60.0 J of energy m/s What is the GPE of a 99.0 kg world-class diver standing on the edge of a 20.0 m platform? J A.450 kg apple hangs from a tree branch exactly 13.0 m from the ground. What is its GPE? 57.3 J How much KE would the same.450 kg apple have after falling only 5.0 of the 13.0 meters? J How much KE would the same apple have just before it hits the ground? Explain 57.3 J KE =PE

6 Remember that KEtotal = PEtotal Work = PE WORK = KE Make sure you understand the concepts of PE and KE and transformations. See page 110 in your text. Describe the energy transformations involved as a pendulum swings back and fourth - once All PE All PE KE PE KE PE KE PE KE PE All KE Remember that it is measured in N m or Joules (J). It s the same thing Law of Conservation of Energy What does the Law state? Under ideal conditions energy is not created or destroyed It is only converted from one form to another Remember DON T JUST THINK ABOUT PLUGGING IN NUMBERS. Anybody can plug numbers into equations. UNDERSTAND what the numbers tell you about the world you live in. There are LOTS of ways to ask questions about the concepts we ve covered you know that. Think of as many possible questions that could be asked and write them down. Think of both qualitative and quantitative questions. Don t limit yourself to the easy stuff challenge yourself. LOOK at all of your notes, homework, labs, old tests, Chapters 1-8, 21, 22 of the TEXT and work through the practice final. Study for YOURSELF NOT from others.