TTaking aking oon n tthe he TTAKSAKS ((TOTTTOTT))February 2008February 2008

Objective 5- PhysicsObjective 5- Physics

Objective 5: Physics Objective 5: Physics Motion, Forces, and EnergyMotion, Forces, and Energy

*8 questions on the 10*8 questions on the 10thth grade TAKS grade TAKS

*11 questions on 11*11 questions on 11thth grade TAKS grade TAKS

FORMULA CHARTFORMULA CHART

Another tool for Another tool for success on the test.success on the test.

Formula in WordsFormula in Words Formula in SymbolsFormula in Symbols

Clarification…….Clarification…….

1

Clarification…….Clarification…….

v = v = dd tt

Sometimes the Sometimes the question will use the question will use the word word VELOCITYVELOCITY instead of speed.instead of speed.

• A place to A place to look for a look for a missing missing number number

• Determine Determine what the what the units should units should bebe

Practice Problem #1Practice Problem #1

A person pushes a large box across a level floor A person pushes a large box across a level floor by applying a horizontal force of 200 N. If the by applying a horizontal force of 200 N. If the person pushes the box a distance of 5 meters in person pushes the box a distance of 5 meters in 10 seconds, how much work does the person do 10 seconds, how much work does the person do on the box?on the box?

A 2000 joulesA 2000 joules

B 1000 joulesB 1000 joules

C 400 joulesC 400 joules

D 100 joulesD 100 joules

force of 200 Nforce of 200 Ndistance of 5 metersdistance of 5 meters

10 seconds10 seconds workwork

Work =force x distanceWork =force x distance

W=FdW=Fd

W= (200N)(5m) = W= (200N)(5m) = 1000 joules1000 joules

*notice 10 seconds was not needed

Practice Problem #2Practice Problem #2

In this circuit, how much In this circuit, how much current flows through current flows through the light bulb?the light bulb?

A 0.75 ampA 0.75 amp

B 1.50 ampsB 1.50 amps

C 2.0 ampsC 2.0 amps

D 3.0 ampsD 3.0 amps

currentcurrent

CurrenCurrentt = = voltage voltage = = V V

resistance R resistance R

Current = Current = 1.5 volts1.5 volts = = 0.75 amp0.75 amp 2.0 2.0 ohmsohms

Let’s Practice……..Let’s Practice……..

*work on problems #1-5 on your *work on problems #1-5 on your worksheetworksheet

Two steppers…..Two steppers…..

•Problems that involve the use of Problems that involve the use of two formulastwo formulas

•The two formulas have a common The two formulas have a common termterm

Two Stepper #1Two Stepper #1

What is the net force acting on a 90.0 kg race-What is the net force acting on a 90.0 kg race-car driver while the race car is accelerating car driver while the race car is accelerating from 0 to 44.7 m/s in 4.50 s? from 0 to 44.7 m/s in 4.50 s?

A 9.8 NA 9.8 N

B 20 NB 20 N

C 201 NC 201 N

D 894 ND 894 N

forceforce

F=maF=ma

m= 90.0 kgm= 90.0 kg

90.0 kg90.0 kg

a= ____a= ____

F= ?F= ?

We need to know “a”, to get our answer. We need to know “a”, to get our answer. Let’s find another equation. Let’s find another equation.

a=a=vvff-v-vii

tt

a=a=44.7m/s-0m/s44.7m/s-0m/s

4.50 s4.50 s

9.9 m/s9.9 m/s22

D 894 ND 894 N

00 to to 44.7 m/s44.7 m/s in in 4.50 s4.50 s??

Two stepper #2………………Two stepper #2………………

Starting from rest at the center of a Starting from rest at the center of a skating rink, two skaters push off from skating rink, two skaters push off from each other over a time period of 1.2 s. each other over a time period of 1.2 s. What is the force of push by the smaller What is the force of push by the smaller skater?skater?

A 16 N B 32 N C 88 N D 100 NA 16 N B 32 N C 88 N D 100 N

forceforce

F=maF=ma

smallersmaller

m=40 kgm=40 kg

a=_____a=_____

..another ..another equationequation

a=a=vvff-v-vii

tt

restrest

1.2 s1.2 sa=a= 3.0 m/s-0m/s3.0 m/s-0m/s

1.2 s1.2 s

2.5 m/s2.5 m/s22

D 100 ND 100 N

FF = m x a and W = = m x a and W = FF x d x d

WW= F x d and P = = F x d and P = WW

tt

Two steppers: other common Two steppers: other common combinationscombinations

Conceptual QuestionsConceptual Questions

Energy:Energy: the ability to cause the ability to cause changechange

The Sun is The Sun is the #1 source the #1 source of energy for of energy for EarthEarth

Energy can be transformed from one Energy can be transformed from one form to another.form to another.

UV

Energy can be transformed from one Energy can be transformed from one form to another.form to another.

PhotosynthesisPhotosynthesis

Which of the following is an example of solar energy Which of the following is an example of solar energy being converted into chemical energy?being converted into chemical energy?

a.a. Plants producing sugar during the dayPlants producing sugar during the dayb.b. Water evaporating and condensing in the Water evaporating and condensing in the water cyclewater cyclec.c. The sun unevenly heating Earths surfaceThe sun unevenly heating Earths surfaced.d. Lava erupting from volcanoes for many daysLava erupting from volcanoes for many days

The Law of Conservation of Energy:The Law of Conservation of Energy: The total energy of a closed system The total energy of a closed system is constant.is constant.

An inventor claims to have created an internal An inventor claims to have created an internal combustion engine that converts 100 kJ of combustion engine that converts 100 kJ of chemical energy from diesel fuel to 140 kJ of chemical energy from diesel fuel to 140 kJ of mechanical energy. This claim violates the mechanical energy. This claim violates the law of conservation of --law of conservation of --

a.a. momentummomentumb.b. inertiainertiac.c. energyenergyd.d. massmass

A helpful hint……………..A helpful hint……………..

Gravitational potential energy = Potential EnergyGravitational potential energy = Potential Energy

If the energy of a closed system changes, If the energy of a closed system changes, then you will observe changes in the then you will observe changes in the

systemsystem

Energy of Energy of a Systema System

WorkingWorking

W=F x dW=F x d•See a change See a change in motionin motion

HeatingHeating

Q=mcQ=mctt•Feel a Feel a temperature temperature changechange RadiatingRadiating

V = V = ff•Hear soundHear sound

•See lightSee light

Heating……Heating……

• Convection!!!!!!Convection!!!!!!

• The answer any time The answer any time the words: air, the words: air, liquid, water or fluid liquid, water or fluid are used.are used.

• When in doubt When in doubt guess convection.guess convection.

•Reflection:Reflection: echo echo

Wave behavior……….Wave behavior……….

When a DVD is read, laser light touches the When a DVD is read, laser light touches the DVD surface and is then measured at location DVD surface and is then measured at location A. What allows light to return to location A after A. What allows light to return to location A after striking the DVD surface?striking the DVD surface?

a.a. ConductionConduction c. Magnificationc. Magnificationb.b. RefractionRefraction d. Reflectiond. Reflection

•Refraction:Refraction: bending of wave bending of wave when it enters a new substance when it enters a new substance (medium)(medium)

Wave behavior……………..Wave behavior……………..

air

water

When trying to spear a fish in water, a When trying to spear a fish in water, a person needs to take into account the way person needs to take into account the way light bends as it moves from water into air. light bends as it moves from water into air. The bending of light as it passes from one The bending of light as it passes from one medium into another is known as --medium into another is known as --

a.a. reflectionreflection c.c. diffractiondiffractionb.b. refractionrefraction d.d. polarizationpolarization

•Resonance:Resonance: one vibrating object one vibrating object causing another object to start causing another object to start vibrating (musical instruments)vibrating (musical instruments)

Sound….requires vibrationsSound….requires vibrations

A guitar player is seated next to a piano. The A guitar player is seated next to a piano. The piano player strikes an E key on the piano. piano player strikes an E key on the piano. The guitarist reports that this causes the E The guitarist reports that this causes the E string on his guitar to vibrate. What is the string on his guitar to vibrate. What is the name of this phenomenon?name of this phenomenon?

a.a. PolarizationPolarization c.c. ReflectionReflectionb.b. ResonanceResonance d.d. DiffractionDiffraction

•Diffraction:Diffraction: waves spreading out waves spreading out when they pass through an when they pass through an openingopening

Wave behavior……………….Wave behavior……………….

D

The diagram below shows The diagram below shows waves approaching a waves approaching a barrier. Which pattern will barrier. Which pattern will form after the waves pass form after the waves pass through the opening in the through the opening in the barrier? barrier?

A

B

C

D

Don’t forget……….Don’t forget……….

• Speed of light and soundSpeed of light and sound

TOTTTOTT: You can do it!: You can do it!

ConvectionConvection

Two SteppersTwo Steppers