Objective 5…TAKS 10th and 11th grades Home slide Questions from TAKS regarding force and motion : Questions from TAKS regarding waves: Questions from TAKS regarding energy transformations: Questions from TAKS about CIRCUITS Interactive non-TAKS quizzes on the internet Link to 10th grade study guide Scroll to p.307 for objective 5 Link to 11th grade study guide Scroll to p.366 for objective 5

Force and Motion Speed Force, Work, Power Newton’s laws Home Force and Motion Speed Force, Work, Power Newton’s laws Momentum, Acceleration Machines, Efficiency

Back to force and motion Home Back to force and motion Speed

Back to force and motion Home Back to force and motion An ant crawled from Point A to Point B in 4.0 seconds. To the nearest tenth, what was the ant’s speed in centimeters per second? Record and bubble in your answer on the answer document. 4cm ÷ 4 s = 1 cm/s 20

Back to force and motion The picture shows the position of a ball every 0.25 second on a photogram. Using a ruler, determine the velocity of the ball. F 3.5 cm/s G 10.5 cm/s H 14.0 cm/s J 28.0 cm/s Home Back to force and motion Speed…velocity = distance ÷ time 3.5 ÷ .25 3.5 cm The ruler from your formula chart: 4

Back to force and motion Home Back to force and motion A cold front moves from Abilene to College Station in 6.0 hours. What is its average speed in km/h? F 0.018 km/h G 16 km/h H 58 km/h J 67 km/h 200 400 km ÷ 6 hours = 67 km/h 200 50

Back to force and motion Speed = distance/time Known speed = 1000/3 = 333.33 333.33 = unknown distance ÷ 8.4 333.33 x 8.4 = unknown distance Home Back to force and motion Observing an approaching thunderstorm and using a stopwatch, a student finds that it takes 8.40 seconds for thunder to be heard after a lightning bolt strikes. The student has learned that it takes 3.0 seconds for sound to travel 1000 m. How far away is the storm? F 119 m G 185 m H 2800 m J 8400 m 4

Back to force and motion 12 ÷ 8 = 1.5 Home Back to force and motion 15 ÷ 9 = 1.67 14 ÷ 12 = 1.16 11 ÷ 15 = .73 The diagram represents the total travel of a teacher on a Saturday. Which part of the trip is made at the greatest average speed? F Q G R H S J T 40

Back to force and motion Home Back to force and motion 8000 ÷ 8.5 =

Back to force and motion A car traveled 150 km in 2.5 hours. What was its average speed in km per hour? Record and bubble in your answer on the answer document. Home Back to force and motion Speed = distance ÷ time 150 ÷ 2.5 60 km/h 20

Back to force and motion Home Back to force and motion Force/ Work/ Power

Back to force and motion The frog leaps from its resting position at the lake’s bank onto a lily pad. If the frog has a mass of 0.5 kg and the acceleration of the leap is 3 m/s2, what is the force the frog exerts on the lake’s bank when leaping? A 0.2 N B 0.8 N C 1.5 N D 6.0 N Home Back to force and motion Force = mass x acceleration Force = .5 x 3 11

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Back to force and motion How much work is performed when a 50 kg crate is pushed 15 m with a force of 20 N? F 300 J H 1,000 J G 750 J J 15,000 J Home Back to force and motion Work = force x distance ? = 20 x 15 42

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Back to force and motion Home Back to force and motion The table shows times required for the same toy car to travel 10 m across an identical section of a floor after it is pushed. The difference in times was probably caused by differences in — A force exerted B surface friction C air resistance D car mass It is hard to duplicate your muscle force exactly, with each trial. These 3 variables remained constant each time. 13

Back to force and motion Home Which lever would require the least force to lift a box with a mass of 10 kilograms? Back to force and motion

Back to force and motion How much force is needed to accelerate a 1,300 kg car at a rate of 1.5 m/s 2? F 867 N G 1,950 N H 8,493 N J 16,562 N Home Back to force and motion Force = mass x acceleration Force = 1,300 x 1.5 8

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Back to force and motion A mechanic used a hydraulic lift to raise a 12,054 N car 1.89 m above the floor of a garage. It took 4.75 s to raise the car. What was the power output of the lift? A 489 W B 1815 W C 4796 W D 30,294 W Home Back to force and motion Power = work / time Work = force x distance Power = (force x distance) / time Power = 12054 x 1.89 / 4.75 21

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Back to force and motion If a force of 100 newtons was exerted on an object and no work was done, the object must have — A accelerated rapidly B remained motionless C decreased its velocity D gained momentum Home Back to force and motion Work is force times distance. No work means either force or distance are missing. 45

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Back to force and motion The weight lifter used a force of 980 N to raise the barbell over her head in 5.21 seconds. Approximately how much work did she do in raising the barbell? F 380 J H 2,000 J G 982 J J 10,000 J Home Back to force and motion Don’t need time for work. Work = Force X distance ? = 980 X 2.04 54

Back to force and motion Home Back to force and motion Newton’s Laws

Back to force and motion Home If she releases it forward, Newton’s law says that she will move in the opposite direction. Back to force and motion The illustration above shows a student about to throw a ball while standing on a skateboard. Which illustration below correctly shows the skateboard’s direction of motion after the student releases the ball? 1

Back to force and motion Home After shooting a cannonball, a cannon recoils with a much lower velocity than the cannonball. This is primarily because, compared to the cannonball, the cannon has a — F much greater mass G smaller amount of momentum H greater kinetic energy J smaller force applied to it Newton’s law…for every action there is an equal and opposite reaction. 12

Back to force and motion Which of these is the best description of the action-reaction force pair when the space shuttle lifts off from the launch pad? A The ground pushes the rocket up while exhaust gases push down on the ground. B Exhaust gases push down on air while the air pushes up on the rocket. C The rocket pushes exhaust gases down while the exhaust gases push the rocket up. D Gravity pulls the rocket exhaust down while friction pushes up against the atmosphere. Back to force and motion Home 41

Back to force and motion Home Back to force and motion

Back to force and motion Which factor would most likely cause a communications satellite orbiting Earth to return to Earth from its orbit? F An increase in the satellite’s forward momentum G An increase in solar energy striking the satellite H A decrease in the satellite’s size J A decrease in the satellite’s velocity Home Back to force and motion If the speed (velocity) of the satellite decreases, the earth’s gravity will ‘win’ and pull it down. 38

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Momentum/ Acceleration Home Back to force and motion Momentum/ Acceleration

Back to force and motion A ball moving at 30 m/s has a momentum of 15 kg·m/s. The mass of the ball is — A 45 kg B 15 kg C 2.0 kg D 0.5 kg Back to force and motion Home Distance/time Given: velocity or speed momentum Unknown: mass Momentum ÷ velocity = mass 15 ÷ 30 = 27

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Back to force and motion Home Back to force and motion Which bike rider has the greatest momentum? A A 40 kg person riding at 45 km/h B A 50 kg person riding at 35 km/h C A 60 kg person riding at 25 km/h D A 70 kg person riding at 15 km/h 40 x 45 = 1800 50 x 35 = 1750 60 x 25 = 1500 70 x 15 = 1050 3

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Home Back to force and motion 1 m per 1 sec He was staying still for a while. 2 m per 1 sec According to this graph, what was the bicycle’s acceleration between 6 and 10 seconds? A 0.0 m/s 2 B 0.65 m/s 2 C 1.6 m/s 2 D 6.5 m/s 2 41

Back to force and motion A catapult was designed to project a small metal ball at a target. The resulting data are shown in the table. Which of these might explain the difference between the calculated and actual distances? A The ball landed short of the calculated distance because of an increase in momentum. B Air resistance caused the ball to land short of the calculated distance. C Initial mass of the ball changed with each trial. D The metal ball was too small for accurate measurements to be made. Air resistance slows anything down. Home Back to force and motion 43

Back to force and motion How many newtons of force does a 50.0 kg deer exert on the ground because of gravity? Record and bubble in your answer on the answer document. Home Back to force and motion Force = mass x acceleration of gravity 50 kg x 9.8 = 490 20

Back to force and motion What is the potential energy of the rock? A 59,900 joules B 64,600 joules C 93,100 joules D 121,600 joules Home Back to force and motion Mass x accel..gravity x height = 95 X 9.8 X 100 = 41

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Back to force and motion Objects of the same mass but of different sizes and shapes were dropped from a given height. Their rates of free fall were measured and recorded. Which of the following is most likely the question this experiment was designed to answer? F How does height affect the force of gravity? G How does gravity affect objects of different densities? H How do mass and weight affect falling objects? J How do size and shape affect an object’s rate of free fall? Home Back to force and motion All were dropped from a “given height”. Density is not as important in freefall as wind resistance and Bernoulli's Principle Mass is constant through the universe. Weight depends on gravity of the planet you’re on. Objects were same mass, but different sizes and shapes which could include objects with different kinds of wind resistance and Bernoulli's Principle. 52

Back to force and motion Home Back to force and motion In a movie, meteoroids make several microscopic holes in a pressurized cabin in the weightless environment of a spaceship. The astronauts search for the holes by spraying water droplets from a container. If this were an actual situation, what effect should be expected? F The drifting water droplets float to the location of the holes. G After falling to the floor, the water forms a stream leading to the holes. H The water droplets form a large sphere of water that moves away from the holes. J Pumping the trigger on the spray container increases the air pressure in the cabin. http://lessons.harveyproject.org/development/general/diffusion/diffnomemb/diffnomemb.html The sprayed water will go from high concentration in the pressurized cabin to the place of ‘no’ molecules…vacuum of space. 42

Back to force and motion Home Back to force and motion Machines/ Efficiency

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Back to force and motion Home Back to force and motion

Back to force and motion Which lever arrangement requires the least effort force to raise a 500 N resistance? Home Back to force and motion E = ? E = ? R = 500 R = 500 E = ? E = ? R = 500 R = 500 46

Back to force and motion What is the efficiency of an air conditioner if there is a work input of 320 J and a work output of 80 J? F 4% G 25% H 240% J 400% Home Back to force and motion 80 / 320 x 100 = 10

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Back to force and motion The diagram shows an electric motor lifting a 6 N block a distance of 3 m. The total amount of electrical energy used by the motor is 30 J. How much energy does the motor convert to heat? F 9 J G 12 J H 18 J J 21 J Home Back to force and motion Joules means work. 30 J is the real work. Force x distance is the ideal work. 48

Back to force and motion Home Back to force and motion Real work – ideal work = friction..heat 30 - 18 = 12 joules of heat

Back to force and motion The diagram shows an electric motor lifting a 6 N block a distance of 3 m. The total amount of electrical energy used by the motor is 30 J. How much energy does the motor convert to heat? F 9 J G 12 J H 18 J J 21 J Home Back to force and motion 48

Waves Waves in general Polarization Reflection, refraction Home Waves Waves in general Polarization Reflection, refraction Interference, resonance

Which illustration best demonstrates compression waves? Back to waves Home Which illustration best demonstrates compression waves? Transverse Compression Both Transverse and Compression Not applicable 37

Home Back to waves

Home Back to waves .5 seconds Put twice the waves in .5 seconds means each wavelength would be ½ of 1.25 cm. 1.25cm ÷ .5 = .625 cm

F improve emission of infrared radiation A solar heater uses energy from the sun to heat water. The heater’s panel is painted black to — F improve emission of infrared radiation G reduce the heat loss by convection currents H improve absorption of infrared radiation J reduce the heater’s conducting properties Home Back to waves 50

At 0°C sound travels through air at a speed of 330 m/s At 0°C sound travels through air at a speed of 330 m/s. If a sound wave is produced with a wavelength of 0.10 m, what is the wave’s frequency? F 0.0033 Hz G 33 Hz H 330 Hz J 3300 Hz Home Don’t need temp. Back to waves Velocity = frequency X wavelength 330 = ? X 0.10 330 ÷ 0.10 = ? X 0.10 ÷ 0.10 330 ÷ 0.10 = frequency 38

Which wave has the greatest velocity? Home Back to waves 1 x 2 2 x 8 3 x 3 4 x 1 Velocity = frequency times wavelength 7

Home Back to waves

Home Back to waves

Home Back to waves This graph shows the absorption spectrum for a certain pigment molecule. To a human, this pigment would most likely appear — A blue B green C yellow D orange Whatever is not absorbed, is reflected. Our eyes see the reflected light. 51

When trying to spear a fish in water, a person needs to take into account the way light bends as it moves from water into air. The bending of light as it passes from one medium into another is known as — F reflection G refraction H diffraction J polarization Home Back to waves Diffraction is when the light waves seem to bend and spread out 14

Home Back to waves

Home Back to waves

A frequency of the vibration produced B strength of the plucking force The pitch of a sound made by plucking a guitar string is determined by the — A frequency of the vibration produced B strength of the plucking force C distance between the strings D shape of the guitar body Home Back to waves vibrations per second Affects amplitude (loud/soft.) Distance between strings enables better finger agility. 55 Affects acoustics or echoing or resonance.

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The second tuning fork starts to vibrate because of — F interference One tuning fork is struck and placed next to an identical fork. The two forks do not touch. The second tuning fork starts to vibrate because of — F interference G the Doppler effect H resonance J standing waves Home Back to waves Interference Set the tuning forks side by side. Strike one to start it vibrating, then stop it with your hand. The fork that you did not strike will be resonating.   32