Transcript Document

Objective 5
The student will demonstrate an
understanding of motion, forces
and energy
4. Science Concept
Integrated Physics and Chemistry
•
The student knows the concept of force and motion
evidence in everyday life. The student is expected to:
A) Calculate speed, momentum, acceleration, work and
power in systems such as in the human body, moving
toys, and machines
B) Investigate and describe applications of Newton’s laws
such as in vehicle constraints, sports activities,
geological processes and satellite orbits
C) Investigate and demonstrate [mechanical advantage
of] efficiency of various machines such as levers,
motors, wheels and axles, pulleys and ramps
4B
IPC
C
The frog leaps from its resting position at the
lake’s bank onto a lily pad. If the frog has a mass
of 0.5 kg and the acceleration of the leap is 3
m/s2, what is the force the frog exerts on the lake’s
bank when leaping?
A 0.2 N 0.5 x 3
B 0.8 N
C 1.5 N = 1.5 N
D 6.0 N
4A
IPC
D
A ball moving at 30 m/s has a
momentum of 15 kg.m/s. The
mass of the ball is ___
A
B
C
D
45 kg
15 kg
2.0 kg
0.5 kg
Momentum divided
by Velocity will give
you the Mass
So 15 divided by 30
= 0.5 kg
If a force of 100 newtons was exerted on
an object and no work was done, the
object must have ---
It didn’t move
A
B
C
D
accelerated rapidly
remained motionless
decreased it velocity
gained momentum
0
4A
IPC
B
= 100 x d
What distance
could be
plugged in to
get 0?
0 = 100 x 0
So what can you say about the distance the object traveled?
4A
IPC
A 1004
How much work is performed when a 50 kg
crate is pushed 15 m with a force of 20N?
A
B
C
D
300 J
750 J
1,000 J
15,000 J
W = 20 x 15
300 = 20 x 15
1.5
km/min
1.7
km/min
1.2
km/min
0.7
km/min
The diagram represents the total travel of a
teacher on a Saturday. Which part of the trip
is made at the greatest average speed?
A Q
B R
C S
D T
4A
IPC
C 1003
4A
IPC
D 1003
A car traveled 150 km in 2.5 hours. What
was its average speed in km per hour?
A
B
C
D
37.5 km/h
450 km/h
75 km/h
60 km/h
150 divided by 2.5
= 60 km/hrs
How much force is needed to accelerate
a 1,300 kg car at a rate of 1.5 m/s2?
A 867 N
B 1,950 N
C 8,493 N
D 16,562 N
1300 x 1.5
= 1950 N
4A
IPC
B 1003
A mechanic used a hydraulic lift to raise
a 12,054 N car 1.89 m above the floor of
a garage. It took 4.75 s to raise the car.
What was the power output of the lift?
A
B
C
D
489 W
1815 W
4796 W
30,294 W
4A
IPC
C
11/04
Work = 12054 x 1.98
Work = 22782.06
P = 22782.06 divided
by 4.75 seconds
P = 4796.22
Round this
number
Which bike rider has the greatest momentum?
A
B
C
D
A 40 kg person riding at 45 km/h
A 50 kg person riding at 35 km/h
A 60 kg person riding at 25 km/h
A 70 kg person riding at 15 km/h
4A
IPC
A
10/04
40 x 45 = 1800
50 x 35 = 1750
60 x 25 = 1500
70 x 15 = 1050
A horizontal force of 600 N is used to push a
box 8 m across a room. Which of these
variables must be known to determine the
power used in moving the box?
To figure Power we need to
divide the work by the
4A
IPC
C
11/05
We can figure
Work because
we know the
force &
box
distance
A The weight of the box
B The potential energy of the
C The time it takes to move the box
D The length of the box
Is the graphed line
increasing,
decreasing or
staying the same?
What number would
represent no increase
or decrease?
4A
IPC
A
11/04
According to this graph, what was the bicycle’s
acceleration between 6 and 10 seconds?
A
B
C
D
0.0 m/s2
0.65 m/s2
1.6 m/s2
6.5 m/s2
4A
IPC
D
11/05
A 0.50 kg ball with a speed of 4.0 m/s strikes a
stationary 1.0 kg target. If momentum is
conserved, what is the total momentum of the
ball and target after the collision?
A
B
C
D
0.0 kgm/s
0.5 kgm/s
1.0 kgm/s
2.0 kgm/s
A woman lifts a 57-newton weight a distance
of 40 centimeters each time she does a
particular exercise. It takes her 0.60 second
to lift the weight. How much power does she
supply for lifting the weight one time?
A
B
C
D
24 W
34 W
38 W
95 W
57 x 40 = 2280
to find Work
2280 divded by 0.60
seconds
= 3800
4A
IPC
c
11/06
The speed of sound in human tissue is
about 1600 m/s. If an ultrasound
pulse takes 1.5 x 10-5s to travel
through a tissue, what is the thickness
of the tissue?
A 2.4 km
B 2.4 m
C 23 cm
D 24 mm
4A
IPC
D
11/05
4A
IPC
D
11/05
Starting from rest at the center of a skating rink,
two skaters push off from each other over a
time period of 1.2 s. What is the force of the
push by the smaller skater?
A 16 N
B 32 N
C 88 N
D 100 N
4A
IPC
JD
11/05
The table contains data for two wrecking balls
being used to demolish a building. What is the
difference in momentum between the two
wrecking balls?
A 300 kgm/s
B 200 kgm/s
C 150 kgm/s
D 0 kgm/s
4A
IPC
C
11/06
The table above shows experimental data collected
when four cars moved along a straight-line path.
According to these data, which car moved with a
constant acceleration of 2 m/s2?
A
B
C
D
Car Q
Car R
Car S
Car T
4A
IPC
D
11/06
A cyclist moves at a constant speed of 5 m/s.
If the cyclist does not accelerate during the
next 20 seconds, he will travel ---
A
B
C
D
0m
4m
50 m
100m
What is the net force exerted on a 90.0 kg
race-car driver while the race car is
accelerating from 0 to 44.7 m/s in 4.50 s?
A
B
C
D
9.8 N
20 N
201 N
894 N
4A
IPC
JD
11/06
An advertisement claims that a certain truck
has the most powerful engine in its class. If
the engine has more power, which of the
following can the truck’s engine do,
compared to every other engine in its class?
A
B
C
D
Produce fewer emissions
Operate more efficiently
Perform work faster
accelerate longer
4A
IPC
HC
11/06
4A
IPC
B
10/06
A driver traveled 270 km in 3 hours. The
driver’s destination was still 150 km away.
What was the driver’s average speed at this
point?
A
B
C
D
40 km/h
90 km/h
140 km/h
420 km/h
4A
IPC
D
11/06
A 0.50 kg ball with a speed of 4.0 m/s strikes a
stationary 1.0 kg target. If momentum is
conserved, what is the total momentum of the
ball and target after the collision?
A 0.0 kgm/s
B 0.5 kgm/s
C 1.0 kgm/s
D 2.0 kgm/s
**duplicate – change data and correct answer
A person pushes a large box across a level
floor by applying a horizontal force of 200 N.
If the person pushes the box a distance of
5 meters in 10 seconds, how much work
does the person do on the box?
A
B
C
D
2000 joules
1000 joules
400 joules
100 joules
4A
IPC
B
10/06
4A
IPC
B
11/06
A 1-kilogram ball has a kinetic energy of
50 joules. The velocity of the ball is ---
A
B
C
D
5 m/s
10 m/s
25 m/s
50 m/s
4A
IPC
HC
11/06
The 500 g cart is moving in a straight line at a
constant speed of 2 m/s. Which of the following
must to 250 g toy car have in order to maintain
the same momentum as the cart?
A An acceleration of 5 m/s2 for 2 seconds
B A potential energy of 20 J
C A constant velocity of 4 m/s
D An applied force of 5 N for 5 seconds
4A
IPC
D
10-04
An ant crawled from point A to Point B in
4.0 seconds. TO the nearest tenth, what
was the ant’s speed?
A 4.7 cm/s
B 1.175 cm/s
B 1.18 cm/s
D 1.2 cm/s
4A
IPC
HC
11/04
The weight lifter used a force of 980 N to raise
the barbell over her head in 5.21 seconds.
Approximately how much work did she do in
raising the barbell?
A 380 L
B 982 J
C 2,000 J
D 10,000 J
The table shows time
required for the same toy
car to travel 10 m across
an identical section of a
floor after it is pushed.
The difference in times
was probably caused by
differences in --A
B
C
D
force exerted
surface friction
air resistance
car mass
Toy Car Speed
Trial
1
2
3
4
Time (s)
5
7
4
7
4B
IPC
A
10/03
4B
IPC
D
11/06
A hockey player pushed a puck toward the
opposite side of a level ice rink. The player
expected the puck to continue all the way
across the ice, but the puck slowed and
stopped before reaching the other side.
Which of these best explains why the puck
failed to slide all the way to the opposite side?
A
B
C
D
The puck’s temperature changed.
An upward force acted on the puck.
The puck’s momentum remained unchanged.
An opposing force acted on the puck.
Which of these is the best description of the
action-reaction force pair when the space
shuttle lifts off from the launchpad?
4B
IPC
C
11/04
A The ground pushes the rocket up while
exhaust gases push down on the ground.
B Exhaust gases push down on air while the
air pushes up on the rocket.
C The rocket pushes exhaust gases down while
the exhaust gases push the rocket up.
D Gravity pulls the rocket exhaust down while
friction pushes up against the atmosphere.
Car velocity = 6.3 m/s
Driver velocity = 6.3 m/s
Driver mass = 100 kg
Car velocity = 0 m/s
Car velocity = 0 m/s
Driver velocity = 6.3 m/s Driver velocity = m/s
Driver mass = 100 kg
Driver mass = 100 kg
4B
IPC
630
11/06
The pictures show how an air bag functions in a
collision. How much momentum in kg m/s does
the air bag absorb from the crash-test dummy if
all the crash-test dummy’s momentum is
absorbed by the air bag?
4B
IPC
C
11/05
Ancient Greeks and Science
The ancient Greeks developed a set of assumptions,
based on observations to explain how the universe works.
These observations led the Greeks to believe that the
universe was composed of four elements: earth, water,
fire, and air. The “theory of natural place” was based on
their observations of those four elements. The theory
stated that anything not in its natural place would move
toward its natural place as soon as an opportunity arose.
The theory of natural place was the foundation for the
modern understanding of the elements. The following
chart describes some observations and assumptions
made by the ancient Greeks.
Object
Observation
Assumption
Rock
Found in or on the ground; if not on the
ground, rocks move toward it at first
opportunity
Rocks are made of earth and seek the ground,
their natural place.
Water
Flows over land
Water has its natural place on the ground.
Fire
Flames flicker upward; the greater the fire, the
higher the flames
Fire’s natural place is in the heavens, above
the atmosphere.
Air
Blows across the land; if trapped in water,
escapes at first opportunity
Air’s natural place is in the space above the
ground.
Burning
wood
Gives off smoke, heat and ash
Tree limbs are made of fire, earth, and air.
Smoke
Found in fires; if not confined, rises or moves
across the land
Smoke is made of fire and air.
Feather
Floats to the ground
Feathers are made of air and earth.
4B
IPC
C
11/05
A leaf from an apple tree falls to the ground more slowly than an
apple falls. As an explanation of this observation, the ancient
Greeks’ theory of the natural place has been replaced by a more
recent theory involving gravitational force and --A
B
C
D
atomic weight
inertial mass
air resistance
kinetic energy
Soap-Making Project
Materials
125 mL cooking oil
100 mL H2O
10 g NaOH
Safety goggles
Apron
500 mL beaker
Stirring rod
Procedures:
•Measure and add 100 mL of H2O to 125 mL of cooking
oil and mix thoroughly.
•Carefully and slowly add 10 g of NaOH while stirring
constantly.
•Stir until paste forms.
•Pour the paste into a mold and let it sit for two days.
•Remove the solid bar from the mold.
Caution:
Keep this soap away from the face and eyes because
traces of
NaOH may still be present on the soap bar. Use this soap
for washing floors and tools only.
4B
IPC
11/05
Soap-Making Project
Materials
125 mL cooking oil
100 mL H2O
10 g NaOH
Safety goggles
Apron
500 mL beaker
Stirring rod
Procedures:
•Measure and add 100 mL of H2O to 125 mL of cooking
oil and mix thoroughly.
•Carefully and slowly add 10 g of NaOH while stirring
constantly.
•Stir until paste forms.
•Pour the paste into a mold and let it sit for two days.
•Remove the solid bar from the mold.
Caution:
Keep this soap away from the face and eyes because
traces of
NaOH may still be present on the soap bar. Use this soap
for washing floors and tools only.
4B
IPC
B
11/05
A wet bar of soap slides 1
meter across a wet tile floor
without appearing to slow
down. Which of these
statements explains why the
bar of soap fails to slow
down?
A. A constant force on an object
produces a constant positive
acceleration.
B. An object in motion tends to
remain in motion in the
absence of an external force.
C. A moving object having
constant velocity contains
kinetic energy.
D. An object’s weight is
proportional to its mass.
4B
IPC
D
11/05
The picture above shows the direction in which
water leaves the scallop’s shell. Which picture
below shows the direction the scallop will move?
4B
IPC
D
11/04
Which factor would most likely cause a
communications satellite orbiting Earth to
return to Earth from its orbit?
A An increase in the satellite’s forward
momentum
B An increase in solar energy striking the
satellite
C A decrease in the satellite’s size
D A decrease in the satellite’s velocity
4B
IPC
GB
11/06
When the air is released from a balloon, the air
moves in one direction, and the balloon moves
in another direction. Which statement does
this situation best illustrate?
A What goes up must come down.
B For every action, there is an equal and
opposite reaction.
C The shape and size of an object affect air
resistance.
D The acceleration due to Earth’s gravity is
9.8 m/s2.
Which of these would cause the gravitational
force between Earth and the sun to
decrease?
4B
IPC
GB
11/06
A An increase in the length of a day on Earth
B An increase in the distance between Earth
and the sun
C An increase in the number of planets
orbiting the sun
D An increase in the masses of Earth and the
sun
4B
IPC
GB
10/06
A
B
C
D
Which graph can represent an object at rest?
4B
IPC
FA
11/04
After shooting a cannonball, a cannon recoils
with a much lower velocity than the
cannonball. This is primarily because,
compared to the cannonball, the cannon has
a --A
B
C
D
much greater mass
smaller amount of momentum
greater kinetic energy
smaller force applied to it
4B
IPC
B
490N
11/04
How many newtons of force does a 50.0 kg
deer exert on the ground because of gravity?
A
B
C
D
49.0N
490N
59.8N
1470N
4B
IPC
D
1004
The illustration above shows a student about to
throw a ball while standing on a skateboard.
Which illustration below correctly shows the
skateboard’s direction of motion after the student
releases the ball?
4D
IPC
GB
The diagram shows an electric motor lifting a 6 N
block a distance of 3 m. The total amount of
electrical energy used by the motor is 30 J. How
much energy does the motor convert to heat?
A
B
C
D
9J
12 J
18 J
21 J
4D
IPC
GB
11/04
What is the efficiency of an air conditioner
if there is a work input of 320 J and a work
output of 80 J?
A
B
C
D
4%
25%
240%
400%
4D
IPC
FA
11/04
A
C
B
D
Which lever arrangement requires the least
effort to raise a 500 N resistance?
4D
IPC
HC
11/06
Which configuration of pulleys and belts shown
below will result in the fastest rotation of spindle
2?
A
C
B
D
4D
IPC
C
11/06
Which of these represents a properly
balanced system?