Wednesday - elyceum-beta

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Transcript Wednesday - elyceum-beta

Wednesday
Test Review for Honors
Homework Answers
Test Tomorrow
On all equations
About the test
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Mostly short answer
Required to show work on questions
Bring calculator
Will be given equations
Will be allowed to bring in unit-symbol
sheet
a
d
GPE
KE
EPE
acceleration
m/s2
distance, displacement
m
Gravitational Potential Energy
Kinetic Energy
J
Elastic Potential Energy J
EE
F
Fi
Fo
Fnet
g
h
m
MA
p
P
t
v
vi
vf
W
W
Electrical Energy J
Force N
Input Force
N
Output Force
N
Net Force
N
acceleration due to gravity m/s2
height m
mass
kg
mechanical advantage
none
momentum
kgm/s
power W
time
s
velocity m/s
initial velocity
m/s
final velocity
m/s
weight N
work
J
J
Answers
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P858
101) 4200 J
102) 30 N
103) 6.8 J
• 106) 222 W
• 107) 2,000,000 J
• 108) 8.81 x 10 15 J
Answers
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Page 857
96a) 14100 kg m/s
96b) 20500 kg m/s
97) 320 kg m/s
98) 4.2 m/s
Answers
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6a) 1.1045 x 10 2 m
6b) 3.45 x 10 -6 s
6c) 1.32948 x 10 5 kg
6d) 3.439 x 10 -2 cm
7) 2.7 x 108 people
8) 7.029 x 10 7 airplanes
9) 5.685 x 10 26 automobiles
Test, answers
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Multiple choice
1)
2)
3)
4)
5)
6)
7)
8)
Test ATest B
D
c
A
c
C
c
C
d
B
b
C
c
A
a
B
b
Test
Test A
9) C
10) D
11) C
12) B
13) C
14) A
15) B
16) C
17) B
18) C
Test B
d
b
a
c
a
c
C
C
C
a
Test
Test A
19) C
20) A
21) B
22) D
23) D
24) C
25) C
Test B
D
C
B
B
B
C
D
Test Short answer
• Why is work output never to work input?
• Answer:
• Friction uses up some of the input work
• How is a pair of scissors a compound
machine…
• Composed of more than one simple
machine
• 1st class levers, wedge, screw
• Compare the size and direction of the
input and output forces shown
• Forces are in same direction
• Output force is larger than input
• If two swimmers compete in race…
• Generally the faster will generate more
power
• But mass also effects the force
• Three children exhaust….
• No motion no work
• Where does energy go…
• Transferred to other parts of the
environment
• Transformed into different types of energy
Do machines reduce the
amount of work we do?
No,
Make it easier by force distance or
direction advantage