Chapter 10 & 11 Bonus Day

8/6/2019 Chapter 10 & 11 Bonus Day

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Jeopardy!


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Work &Power

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Machines Cost Energy

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9001000


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Work & Power 100

In what unit is work measured?


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Work & Power 100

In what unit is work measured?.

Joule


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Work & Power 200

What is another name for a joule ofwork done every second?


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Work & Power 200

What is another name for a joule ofwork done every second?

watt


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Work & Power 300

How much work is done carrying a7.0kg bowling ball across a level 20.0

meter long classroom?


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Work & Power 300

How much work is done carrying a7.0kg bowling ball across a level 20.0

meter long classroom?none


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Work & Power 400

Fido and Spot have the same massand race up a flight of stairs. Fido

beats spot by 3.0 seconds and wins abone. Who did more work?


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Work & Power 400

Fido and Spot have the same massand race up a flight of stairs. Fido

beats spot by 3.0 seconds and wins abone. Who did more work?

Neither, work is the same.


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Work & Power 500

A crane lifts a 2000.0 kg. SUV adistance of 33.0 meters. How much

work did the crane do?


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Work & Power 500

A crane lifts a 2000.0 kg. SUV adistance of 33.0 meters. How much

work did the crane do?

JW

FdW

800,646)33)(8.9)(2000( ==

=


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Work & Power 600

An 80.0 kg. pole vaulter clears a 7.2meter high bar in 1.3 seconds. How

much power does he generate?


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Work & Power 600

An 80.0 kg. pole vaulter clears a 7.2meter high bar in 1.3 seconds. How

much power does he generate?

wattsP

tFdPtWP

15.43423.1/)2.7)(8.9)(80(

//

==

==


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Work & Power 700

An elevator in the Empire StateBuilding generates 38,000.0 watts of

power while rising 430.0 meters in 1.5minutes. What is the mass of theelevator?


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Work & Power 700

An elevator in the Empire StateBuilding generates 38,000.0 watts of

power while rising 430.0 m. in 1.5 min.What is the mass of the elevator?

kgmm

tFdPtWP

58.81190/)430)(8.9(000,38

//

==

==


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Work & Power 800

A 65.0 kg student races up the pathto lunch which is at a 2 slope. How

long is the path if she does 4000.0joules of work?


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Work & Power 800

A 65.0 kg student races up the pathto lunch which is at a 2 slope. How

long is the path if she does 4000.0joules of work?

mddFdW

93.1792sin))(8.9)(65(4000sin

==

=


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Work & Power 900

A dad pulls his 30.0 kg daughter andher 5.0 kg sled across 45.0 m of level

ground with a rope. If he pulls with aforce of 253 N and does 9,220 joulesof work, what angle does the rope

make with the sled?


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Work & Power 900

A dad pulls his 30.0 kg daughter andher 5.0 kg sled across 45.0 m oflevel ground with a rope. If he pulls

with a force of 253 N and does9,220 joules of work, what angledoes the rope make with the sled?

92.35cos)45)(253(9220cos

==

=

FdW


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Work & Power 1000

My 1800 kg. car generates 1300watts of power when I drive 6.0 miles

from my house to school at a constantvelocity. If my house is at anelevation of 5060 ft and the school isat 5310 ft., how many minutes does it

take me to drive to school? (Thereare 3.28 ft in a meter and 5280 ft ina mile)


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Work & Power 1000

My 1800 kg. car generates 1300 watts of power when Idrive 6.0 miles from my house to school at a constantvelocity. If my house is at an elevation of 5060 ft andthe school is at 5310 ft., how many minutes does it takeme to drive to school? (There are 3.28 ft in a meter and5280 ft in a mile)

min24.17sec24.1034

/)28.3/)50605310)((8.9)(1800(1300

//

=

=

==

t

t

tFdPtWP


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What are the units for MechanicalAdvantage?

Machines 100


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Machines 100

What are the units for MechanicalAdvantage?

It is unitless there are none.


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Machines 200

If a machine has a MA of 5, whatdoes this mean?


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Machines 200

If a machine has a MA of 5, whatdoes this mean?

You can lift 5 times the force.


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Machines 300

If the IMA of a machine is 6, and you want to raise anobject 2.0 meters off the ground, how much rope do youhave to pull in?

mdd

ddIMA

ee

re

122/6

/

==

=


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Machines 400

If the MA of a pulley system is 4.2and the IMA is 13.5, what is the

percent efficiency of the pulleys?


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Machines 400

If the MA of a pulley system is 4.2 andthe IMA is 13.5, what is the percentefficiency of the pulleys?

%1.31)100(5.13/2.4

)100(/

==

=

xEff

IMAxMAEff


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Machines 500

A student pulls in 8.3 m of rope tolift a table 1.6 m. If the table weighs

160 lbs. and the student uses 35 lbsof force, what is the percentefficiency of the machine?


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Machines 500

A student pulls in 8.3 m of rope to lift a table 1.6 m. Ifthe table weighs 160 lbs. and the student uses 35 lbs offorce, what is the percent efficiency of the machine?

%12.88100)6.1/3.8/()35/160(

)100(/

==

=

xEff

IMAxMAEff


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Machines 600

An ideal machine can lift an 825.0 kg. elephantusing only 27.0 kg. If the elephant is lifted1.6 m off the ground, how much rope ispulled in?


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Machines 600

An ideal machine can lift an 825.0 kg. elephant usingonly 27.0 kg. If the elephant is lifted 1.6 m off theground, how much rope is pulled in?

mdd

dFdFWW

ee

rreeoutin

89.48)6.1)(825(27 ==

==


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Machines 700

A compound machine is made up of 5simple machines each with a MA of 3

and an IMA of 4. What is the percentefficiency of the compound machine?


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Machines 700

A compound machine is made up of 5simple machines each with a MA of 3

and an IMA of 4. What is the percentefficiency of the compound machine?

%73.231004/3

100/

55==

=

xEff

xIMAMAEff

c

ccc


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Machines 800

A compound machine needs a MA of256 to raise a steel beam. If the MA

of one wheel and axle is 4, how manywheel and axles do you need in thecompound machine to lift the beam?


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Machines 800

A compound machine needs a MA of256 to raise a steel beam. If the MA

of one wheel and axle is 4, how manywheel and axles do you need in thecompound machine to lift the beam?

4)4log(/)256log(44256 ====

nMAMAn

n

c


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Machines 900

The space shuttle has a mass of96,000 kg. With onewheel and axle a

student can lift a 1200 N object using375 N of force. How many completewheel and axles would it take to lift

the shuttle if she can use 375 N offorce?


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Machines 900

The space shuttle has a mass of 96,000 kg. With onewheeland axle a student can lift a 1200 N object using 375 N offorce. How many complete wheel and axles would it take to liftthe shuttle if she can use 375N of force?

72.38.2508

8.2508375/800,940/

800,940)8.9)(000,96(

2.3375/1200/

===

==

==

==

nMAMA

FFMA

NF

FFMA

nn

c

erc

r

er


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Machines 1000

The efficiency of a compoundmachine is 1.01%, it is made up of a

number of simple machines each withan efficiency of 60%. If the IMA ofone of the machines is 5 and you wantto raise a car 2.0 meters, how much

rope much you pull in? (round to thenearest number of machines)


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Machines 1000

The efficiency of a compound machine is 1.01%, it is madeup of a number of simple machines each with anefficiency of 60%. If the IMA of one of the machines is5 and you want to raise a car 2.0 meters, how much rope

much you pull in? (round to the nearest number ofmachines)

mddddIMA

IMA

nEffEff

eerec

c

nn

c

250,906,32/125,953,1/

125,953,15

96.0101.

9

===

==

===


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Cost 100

What is the more common name for awatt-sec?


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Cost 100

What is the more common name for awatt-sec?

joule


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Cost 200

A joule is a very small unit of energy,what is the more common unit of

energy that appears on your ExcelEnergy bill?


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Cost 200

A joule is a very small unit of energy,what is the more common unit of

energy that appears on your ExcelEnergy bill?

kw-hr


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Cost 300

How many joules are there in a

kw-hr?


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Cost 300

How many joules are there in a

kw-hr?

kwhrjouleshrkwwatt 1/000,600,3)1sec/3600)(1/1000( =


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Cost 400

A 1000 watt toaster is operated for 30minutes. How many kw-hrs is this?

kwhrhrwkww 5.min)60/1min)(30)(1000/1)(1000( =


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Cost 500

A 700 watt halogen light bulb isoperated for 8.5 hrs. If energy costs

$.12/kwhr, how much does it cost tooperate the light bulb during thistime?


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Cost 500

A 700 watt halogen light bulb is operated for 8.5 hrs.If energy costs $.12/kwhr, how much does it costto operate the light bulb during this time?

714$.))(1000(

)12)($.5.8)(1)(700(=

kwhrw

hrkww


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Cost 600

A 1500 watt blow dryer is used for23 minutes a day, every day of the

year. If energy costs $.117/kwhr, howmuch does it cost to run the blowdryer for 18 years?


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Cost 600

A 1500 watt blow dryer is used for 23 minutes a day, every day of the year. Ifenergy costs $.117/kwhr, how much does it cost to run the blow dryer for 18

years?

99.441$))(1min)(60)()(1000(

)117)($.18)(365)(1min)(23)(1)(1500(=

kwhryeardayw

yearsdayshrkww


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Cost 700

In a typical house, a 2500 watt ovenoperates for an average of 49 min a

day and a 900 watt microwaveoperates for 26 min a day. If energycosts $.112/kwhr, how much does anaverage family spend on theseappliances over a 7 year period?


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Cost 700

In a typical house, a 2500 watt oven operates for anaverage of 49 min a day and a 900 watt microwaveoperates for 26 min a day. If energy costs $.112/kwhr,how much does an average family spend on theseappliances over a 7 year period?

84.695$60.111$24.584$

60.111$))(1min)(60)()(1000(

)112)($.7)(365)(1min)(26)(1)(900(

24.584$))(1min)(60)()(1000(

)112)($.7)(365)(1min)(49)(1)(2500(

=+=

=

=

Total

kwhryeardayw

yearsdayshrkww

kwhryeardayw

yearsdayshrkww


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Cost 800

A 66.0 kg student climbs 22 stepswhen leaving physics to get back

upstairs every day (each step is 16cm. high). If Excel could capture thatenergy and pay the student$.121/kwhr, how much would thestudent earn climbing the stairsevery day?


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Cost 800

A 66.0 kg student climbs 22 steps when leaving physics to getback upstairs every day (each step is 16 cm. high). If Excelcould capture that energy and pay the student $.121/kwhr, howmuch would the student earn climbing the stairs every day?

565.7$))(000,600,3(

)121)($.1)(74.2276(

74.2276)16)(.22)(8.9)(66(

=

===

EkwhrJ

kwhrJ

JWFdW


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Cost 900

A average McDonalds uses seven 1200watt microwaves on average 70% ofthe time of an entire day. Each statehas a average of 333 McDonaldsrestaurants. If McDonalds neverclose and energy costs $.103/kwhr,

how much does McDonalds spend onmicrowave use in this country in ayear?


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Cost 900

A average McDonalds uses seven 1200 watt microwaves on average 70% of the time of anentire day. Each state has a average of 333 McDonalds restaurants. If McDonalds never closeand energy costs $.103/kwhr, how much does McDonalds spend on microwave use in thiscountry in a year?

016,335,88$))(1)()()()(1000)()((

)103)($.365)(50)(333)(24)(7)(.1)(7)(1200(=

kwhryearcountrystatedaywrestmicro

daysstatesresthrkwmicrow


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Cost 1000

A family spends $334.94/year inlightbulb costs when energy costs

$.105/kwhr. A average lightbulb intheir house uses 68 watts of powerand is on 42% of the time the familyis awake every day. If they generallysleep 7 hours a night, how manylightbulbs do they have in theirhouse?


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Cost 1000

A family spends $334.94/year in lightbulb costs when energycosts $.105/kwhr. A average lightbulb in their house uses 68watts of power and is on 42% of the time the family is awakeevery day. If they generally sleep 7 hours a night, how manylightbulbs do they have in their house?

lightbulbs

kwhryeardaywlightbulb

dayshrkwlightbulbw

18

94.334$))(1)()(1000)((

)105)($.365)(724)(42)(.1)()(?68(=


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Energy 100

What unit is potential energymeasured in?


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Energy 100

What unit is potential energymeasured in?

Joule


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Energy 200

A ball is thrown straight up in the airand caught at the same height. When

is its KE at a maximum?


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Energy 200

A ball is thrown straight up in the airand caught at the same height. When

is its KE at a maximum?The instant it leaves the hand goingup or the instant before it is caught

coming down.


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Energy 300

What can be said about the PE of arock before its dropped off a cliff

and the KE at the bottom of thecliff?


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Energy 300

What can be said about the PE of arock before its dropped off a cliff

and the KE at the bottom of thecliff?

They are equal.


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Energy 400

A plane is traveling eight times as fast as a truck with thesame mass. How much more KE does it have?

timesmm

vmKE

64)1(/)8(

)(

2212

21

2

21

=

=


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Energy 500

A student drops a .1 kg donut off thetop of a 312.0 meter high rise

building. How fast does the donut hitthe ground?


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Energy 500

A student drops a .1 kg donut off thetop of a 312.0 meter high rise building.How fast does the donut hit theground?

smv

ghv

/2.78)312)(8.9)(2(

2

==

=


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Energy 600

A force of 800N is applied to a carthrough its engine. If the 1200 kg car

started from rest, how fast is itgoing at the end of 85 meters?


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Energy 600

A force of 800N is applied to a car through itsengine. If the 1200 kg car started from rest,how fast is it going at the end of 85 meters?

smvv

mvKEFdW

/64.101200)85)(800(

2

2

1

2

21

=

=

===


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Energy 700

A 92.0 kg diver jumps off a 7.5 metertower. How fast is the diver going

after she has fallen and is 2.1 metersabove the water?


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Energy 700

A 92.0 kg diver jumps off a 7.5 meter tower. Howfast is the diver going after she has fallen andis 2.1 meters above the water?

smv

ghv

/29.10)1.25.7)(8.9)(2(

2

==

=


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Energy 900

A skydiver traveling at 23.0 m/s falls240 meters. How fast is he going

after that time?


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Energy 900

A skydiver traveling at 23.0 m/s falls240 meters. How fast is he going afterthat time?

smv

mvmm

mvmvKEmghPE

f

f

of

/34.72

)23()(240)8.9( 2

2

12

2

1

2

212

21

=

=

===


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Energy 1000

A 300 kg. chair lift generates 600 watts ofpower when accelerating from 2.0 m/s to8.0 m/s. How much time does the chair lift

accelerate for?


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Energy 1000

A 300 kg. chair lift generates 600 watts of power when accelerating from2.0 m/s to 8.0 m/s. How much time does the chair lift accelerate for?

sec15/9000600

/

9000)2(300)8(300 2212

21

2

212

21

==

=

==

==

tt

tWP

JW

mvmvKEW of

Chapter 10 & 11 Bonus Day

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Transcript of Chapter 10 & 11 Bonus Day