Transcript Ms. Hughes`

Do Now:
1. An object which weighs 10 N is dropped from
rest from a height of 4 meters above the
ground. What is its total energy when it has
free-fallen 1 meter with respect to the
ground?
2. During a certain time interval, a 20-N object
free-falls 10 meters. The object gains how
many Joules of kinetic energy during this
interval?
Do Now:
1. During a certain time interval, a 20-N object
free-falls 10 meters. The object gains how
many Joules of kinetic energy during this
interval?
Do Now (2/13/12):
•Make a list of
concepts to be
covered on
tomorrow’s test.
Ms. Timson’s
Review to Conquer Physics
Rules of the Game
• There will be tribes, as divided by the teacher
• For each problem which appears on the slide, the tribe will be able to work
together to vote on one answer given only the time which will be written
on the slide.
• Tribes cast their answer using their voting cards only in the time allowed.
• Each team with a correct answer is allowed to cast one vote to remove
another tribe from the island. The teacher will have each tribe cast their
vote simultaneously by writing the color of the tribe they are voting for on
their white board. The teacher will then remove tribes from the island.
• The teacher will track which tribes are in and which tribes are out of the
game with signs on the board.
• If a tribe is voted out, they can reenter the game by answering the next
question correctly to reenter. They will NOT receive a vote for that question
but must wait until the next question.
• Winning tribes will be those still on the island at the end of the game.
• ***The teacher will be the final judge of any conflicts or confusions – and
remember, be respectful and be honest!
1. The unit of work, Joule, is
dimensionally the same as:
A. Newton/second
B. Newton/kilogram
C. Newton∙second
D. Newton∙meter
10 seconds
2. Which of the following quantities refers to
the rate at which work is done?
a. heat
b.kinetic energy
c. efficiency
d.Power
10 seconds
3. A girl pushes a box 5 m by applying a 25 N
horizontal force. What work does she do?
A.10 J
B. 25 J
C. 125 J
D. 550 J
25 seconds
4. Which of the following refers to a machine’s
ratio of output work to input work?
A.IMA
B. efficiency
C. mechanical advantage
D. Reliability
20 seconds
5. If the mechanical advantage of a pulley
system is .95, what effort force must be
exerted to lift a 20.0 N box at constant
velocity?
A.22 N
B.21 N
C.20 N
D. 19 N
20 seconds
6. What angle between the force applied on
an object and its displacement will allows
for maximum work done on the object?
A.0
B.45
C.70
D.90
15 seconds
7. A rope is used to pull a metal box 10 m
across the floor with a force of 500 N. The
rope is held at an angle of 60° with the
floor. How much work does the puller do?
A.3 x 105 J
B.5.0 x 103 J
C.2.5 x 103 J
D.2.5 x 102 J
1 minute
8. In which of the following situations is work
done equal to zero?
a. picking up a book on the floor and putting it
on top of the desk
b.pushing a chair across the room while
applying a horizontal force on it
c. leaning against a concrete wall
d.going down from the first floor to the second
floor
e.coming in late and not doing the drill
1 minute
9. How fast would a 200-kg meteorite have to
travel to have the same energy as a 20,000kg meteorite traveling at 100 m/s?
A.500 m/s
B.5000 m/s
C.1000 m/s
D.10,000 m/s
1 minute
10. The main difference between kinetic energy
and potential energy is that
A. kinetic energy involves position and potential
energy involves motion.
B. kinetic energy involves motion and potential
energy involves position.
C. although both energies involve motion, only
kinetic involves position.
D. although both energies involve position, only
potential involves motion.
30 seconds
11. A force of 8 N is exerted on a 1 kg mass at
rest for 2 m, causing it to move. What is the
change in the object’s kinetic energy?
A.2 J
B. 16 J
C. 8 J
D. 64 J
45 seconds
12. Which energy transformation occurs as a
book falls from the top of your book shelf?
A. the book’s potential energy and kinetic
energy decreases
B. the book’s potential energy increases and
it’s kinetic energy decreases
C. the book’s potential energy decreases and
it’s kinetic energy increases
D. the book’s potential energy and kinetic
energy increases
20 seconds
13. A 3.00 kg toy falls from a height of 10.0 m.
Just before hitting the ground, what will be
its kinetic energy?
A.98.0 J
B. 0.98 J
C. 294 J
D. 29.4 J
1 minute
14. What is the speed of the 3 kg toy that fell
from 10 m in the previous problem just
before it hits the ground?
A.3.33 m/s
B. 14 m/s
C. 5.47 m/s
D. 30 m/s
1 minute
15. As an object is lowered into a deep hole in
the ground, which of the following
assumptions must be made in regard to the
object’s potential energy?
A. The potential energy decreases.
B. The potential energy increases.
C. The potential energy remains constant.
D. The potential energy increases and then
decreases.
45 s
16. John has an object suspended in the air. It
has a mass of 20 kilograms and is 50 meters
above the ground. How much work would
the object do if it was dropped?
a. 100 j
b.1000 j
c. 980 j
d.9800 j
45 seconds
17. A 2 kg rock loses 350 J of potential energy
while falling to the ground. What is the
rock's speed just before it strikes the
ground?
a. 175 m/s
b.350 m/s
c. 18.7 m/s
d.13.2 m/s
45 seconds
18. A force of 70.0 N is used to slide a 10.0 kg
box 5.0 m horizontally from position A to
position B.
How much work is done on the box?
A) 0 J
B) 70 J
C) 350 J
D) 500 J
E) 3500 J
45 seconds
19. A force of 70.0 N is used to slide a 10.0 kg box
5.0 m horizontally from position A to position
B. How much potential energy does the box as
a result of the work done on it?
A) 0 J
B) 70 J
C) 350 J
D) 500 J
E) 3500 J
45 seconds
20. If a 2 kg object undergoes free fall for 50
m, it will lose about ____ J of potential
energy.
A) 0
B) 70
C) 100
D) 200
E) 1000
45 seconds
A 2.0 kg stone is dropped from the top of a cliff that
rises 50.0 meters above ground.
21. What is the potential energy of the stone at the
top of the cliff before it is dropped? (Use the
ground as the base level.)
A) 40 J
B) 100 J
C) 400 J
D) 1000 J
E) 10,000 J
45 seconds
A 2.0 kg stone is dropped from the top of a cliff that
rises 50.0 meters above ground.
22. As it falls, what is the kinetic energy of the stone
at a height of 30 m from the ground?
A) 60 J
B) 200 J
C) 400 J
D) 600 J
E) 1000 J
AB) 4000 J
45 seconds
A 2.0 kg stone is dropped from the top of a cliff
that rises 50.0 meters above ground.
23. As the stone falls it reaches a speed of 20
m/s. What is its kinetic energy at this point?
A) 20 J
B) 40 J
C) 200 J
D) 400 J
E) 600 J
45 seconds
A 2.0 kg stone is dropped from the top of a cliff
that rises 50.0 meters above ground.
24. What is the height of the stone when it has a
speed of 20 m/s?
A) 3 m
B) 4 m
C) 10 m
D) 30 m
E) E) 40 m
45 seconds
A 2.0 kg stone is dropped from the top of a cliff
that rises 50.0 meters above ground.
25. When the stone comes to rest after striking the
ground it has neither potential nor kinetic
energy. The energy was most likely converted to
______ and ______ . (Enter two answer letters.)
A) electricity
B) heat
C) light
D) magnetism
E) Sound
45 seconds
Congratulations!
Good luck tomorrow!
I know you can conquer your
test 