5 pt.
5 pt.
5 pt.
5 pt.
5 pt.
10 pt.
10 pt.
10 pt.
10 pt.
10 pt.
15 pt.
15 pt.
15 pt.
15 pt.
15 pt.
20 pt.
20 pt.
20 pt.
20 pt.
20 pt.
25 pt.
25 pt.
25 pt.
25 pt.
25 pt.
1-5
When energy is added to an
object, what kind of work is
done?
A)
B)
C)
D)
positive
negative
zero
not enough info
1-5A
When energy is added to an
object, what kind of work is
done?
A) positive
1-10
Force
Is the work done on the object
pictured below positive or negative?
distance
1-10A
Force
Is the work done on the object
pictured below positive or negative?
distance
Zero, since the force and
distance are at right angles.
1-15
How much work is done by a car’s
engine when it pushes with a force of
1450 N through a distance of 200
meters?
1-15A
How much work is done by a car’s
engine when it pushes with a force of
1450 N through a distance of 200
meters?
Work = Force x distance
Work = (1450 N)(200 m) = 290,000 J
1-20 expended when a
How many watts are
100-N person walks 3.5 meters up a
flight of stairs in 14 seconds?
1-20Aexpended when a
How many watts are
100-N person walks 3.5 meters up a
flight of stairs in 14 seconds?
Work = Force x distance
Work = (100 N)(3.5 m) = 350 J
Power = Work / Time
Power = (350 J)/(14 sec) = 25 Watts
Suppose that a block of1-25
weight 300-N is lifted
through a height of 5 meters by pushing it up a
ramp 16.5 meters long. How hard must the block
be pushed up the ramp?
5m
16.5 m
Suppose that a block of1-25A
weight 300-N is lifted
through a height of 5 meters by pushing it up a
ramp 16.5 meters long. How hard must the block
be pushed up the ramp?
Energy needed = weight x height = (300 N)(5 m) = 1500 J
Work on Ramp = 1500 J
Work = Force x distance
Force = Work / distance = (1500 J)/(16.5 m) = 90.9 Newtons
5m
16.5 m
2-5
Negative work is done
on a rolling
bowling ball. What happens to the
kinetic energy of the ball?
A)
B)
C)
D)
KE increases
KE does not change
KE decreases
not enough info
2-5A
Negative work is done
on a rolling
bowling ball. What happens to the
kinetic energy of the ball?
C) KE decreases
2-10
True or False:
It is possible for an object to
have a negative kinetic energy.
2-10A
True or False:
It is possible for an object to
have a negative kinetic energy.
False
2-15
What is the KE of a car with mass
1200-kg that is moving at 50 m/sec?
2-15A
What is the KE of a car with mass
1200-kg that is moving at 50 m/sec?
KE = 1/2mv2
KE = 1/2 (1200 kg)(50 m/s)2
KE = 1,500,000 Joules
2-20
Two identical cars are
traveling down the
road -- one moving at twice the speed of the
other. If both apply the brakes, what will
happen?
A)
B)
C)
D)
they both travel the same distance
the faster car will move twice as far
the faster car will move four times as far
not enough info
2-20A
Two identical cars are
traveling down the
road -- one moving at twice the speed of the
other. If both apply the brakes, what will
happen?
C) the faster car will move four times as far
2-25 is pushed by a
A rocket of mass 250-kg
thrust force of 10,000-N through 12
kilometers. How fast is it moving when the
engine shuts off?
2-25A is pushed by a
A rocket of mass 250-kg
thrust force of 10,000-N through 12
kilometers. How fast is it moving when the
engine shuts off?
Work = Change in KE ==> Fd = 1/2mv2
(10,000 N)(12,000 m) = 1/2 (250 kg)v2
v = √[2(10,000 N)(12,000 m)/250 kg]
v = 980 m/sec
3-5
How do you calculate gravitational
potential energy (GPE)?
3-5A
How do you calculate gravitational
potential energy (GPE)?
GPE = weight x height = mgh
3-10
What is the GPE of a 50-kg object
placed at a height of 10 m?
3-10A
What is the GPE of a 50-kg object
placed at a height of 10 m?
GPE = mgh = (50 kg)(10 m/s2)(10 m)
GPE = 5,000 Joules
3-15
A perfect pendulum swings from
rest. How high does it go before it
stops?
A)
B)
C)
D)
lower than originally
the same height as originally
higher than originally
not enough info
3-15A
A perfect pendulum swings from
rest. How high does it go before it
stops?
B) the same height as originally
3-20
An elevator of 550-kg
goes from the first to
the fourth floor. If each floor is 4 meters,
how much GPE does the elevator gain?
3-20A
An elevator of 550-kg
goes from the first to
the fourth floor. If each floor is 4 meters,
how much GPE does the elevator gain?
Weight = 550 kg * 10 m/s = 5,500 N
GPE = weight x height = (5,500 N)(3 x 4 m)
(it’s 3 flights from 1st to 4th floor)
GPE = 66,000 Joules
3-25
Daily Double
How much power does the engine of a
2300-kg elevator put out if it climbs
through 38-m in one minute?
3-25A
How much power does the engine of a
2300-kg elevator put out if it climbs
through 38-m in one minute?
GPE = (2300 kg)(10 m/s2)(38 m) = 874,000 J
Power = GPE / Time = (874,000 J)/(60 sec)
Power = 14,567 Watts
4-5 during the Big
If the universe began
Bang 14 billion years ago with an
energy of 516 gadzillion Joules, how
much energy is there in the universe
right now?
4-5A during the Big
If the universe began
Bang 14 billion years ago with an
energy of 516 gadzillion Joules, how
much energy is there in the universe
right now?
516 gadzillion Joules
When a car slows4-10
down to a stop
where does all of its previous KE go?
A)
B)
C)
D)
it turns into heat
braking energy
into total mechanical energy
not enough info
When a car slows4-10A
down to a stop
where does all of its previous KE go?
A) it turns into heat
When a diver who4-15
weighs 650-N jumps
from a 10-m high diving platform, how
much KE do they hit the water with?
When a diver who4-15A
weighs 650-N jumps
from a 10-m high diving platform, how
much KE do they hit the water with?
GPEinitial = KEfinal
KEfinal = (650 N)(10 m) = 6500 J
4-20down on a
When jumping up and
trampoline, the 450-N jumper leaves the
trampoline with a KE of 3800 J. How high
do they travel?
4-20A
When jumping up and
down on a
trampoline, the 450-N jumper leaves the
trampoline with a KE of 3800 J. How high
do they travel?
KEinitial = GPEfinal = mgh
3800 J = (450 N) h
h = (3800 J)/(450 N) = 8.44 m
A 2-kg ball slides from4-25
rest down a 5-m tall
incline as shown. When it is halfway down,
how fast is it going?
A 2-kg ball slides from
rest down a 5-m tall
4-25A
incline as shown. When it is halfway down,
how fast is it going?
GPEinitial = KE + GPE
(2kg)(10m/s2)(5m) = 1/2 (2kg)v2 + (2kg)(10m/s2)(2.5m)
100 J = v2 + 50 J
v = √(50) = 7.1 m/sec
Where on Earth5-5would you have
the greatest gravitational
potential energy?
5-5A
Where on Earth
would you have
the greatest gravitational
potential energy?
Mount
Everest
5-10
Name the character and movie
that produced this famous quote:
“A wizard is never late… he arrives
precisely when he means to.”
5-10A
Gandalf the Grey, in
LOTR: Fellowship of the Ring
5-15
What is the name of the very
energetic fitness guru who
exercised to the oldies in the
1990’s?
5-15A
Richard Simmons
5-20
In what year was the Great
Pyramid of Giza
constructed?
(±200 years)
5-20A
Roughly 2600 B.C.E.
5-25
What is the title of the
movie set in Iowa in
which a farmer hears
voices, helps ghosts
and plays catch?
5-25A
Field of Dreams