Transcript PPt

4B investigate and describe [applications of]
Newton’s laws such as in vehicle restraints, sports
activities, geological processes, and satellite
orbits;
First Law
Law of Inertia

An object in motion remains in motion or an
object at rest remains at rest unless acted on by
an unbalanced force.
With seat belt.
Without seat belt.
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FIRST LAW

FORCES
 Forces are on one object;
forces are balanced.
 Force to the right = 500N
 Force to the left = 500N
 Net Force = 0N
FIRST LAW
MOTION:
 Object will be at rest or moving at a
constant velocity.
Practice Question 1
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 constant
positive acceleration.
b. A moving object having constant velocity
contains kinetic energy.
c. An object in motion tends to remain in motion in
the absence of an external force.
d. An object’s weight is proportional to its mass.
Practice Question 1
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 constant
positive acceleration.
b. A moving object having constant velocity
contains kinetic energy.
c. An object in motion tends to remain in motion in
the absence of an external force.
d. An object’s weight is proportional to its mass.
Newton’s
Second Law
Acceleration is produced when a force acts on
a mass. The greater the mass (of the object
being accelerated) the greater the amount of
force needed (to accelerate the object).
 EQUATION: FORCE = mass X acceleration
= kg X m/s2
= newtons

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SECOND LAW
FORCES:
 Forces are on one object; forces are
unbalanced.
 Force to right = 200N Force to left: =
50N
 Net Force = 150 N to right

SECOND LAW
MOTION:
 Object will accelerate – change speed
or direction.

Free - Fall
Motion under the force of gravitation only
 Acceleration due to gravity = 9.8 m/s 2

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Practice Question 2
2.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/s 2, what
is the force the frog exerts on the lake’s
bank when leaping?
a. 0.2 N
c. 1.5 N
b. 0.8 N
d. 6.0 N
Practice Question 2
2.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/s 2, what
is the force the frog exerts on the lake’s
bank when leaping?
a. 0.2 N
c. 1.5 N
b. 0.8 N
d. 6.0 N
 F = m x a = 0.5 kg x 3 m/s2 = 1.5 N
Practice Question 3
3. 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
9.8 N
B. 20 N
C. 201 N
D. 894N
A.
Practice Question 3
3. 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
9.8 N
B. 20 N
C. 201 N
D. 894N
A.
Third Law

For every action force there is an equal and
opposite reaction force.
Action Force: Rocket pushes gases down.
 Reaction Force: Gases push rocket up.

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Practice Question 4
4. 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. much greater mass
b. greater kinetic energy
c. smaller amount of momentum
d. smaller force applied to it
Practice Question 4
4. 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. much greater mass
b. greater kinetic energy
c. smaller amount of momentum
d. smaller force applied to it
THIRD LAW
FORCES:
 Forces are on two different objects; Forces
are equal but in opposite directions
 Action Force: Baseball pushes glove
leftward.
 Reaction Force: ___________________
Glove pushes baseball rightward.

THIRD LAW
Action Force: _____________________
Ball pushes bat leftward.
 Reaction Force: Bat pushes ball
rightward.

Question Practice
1. The picture above shows the directions in which water
leaves this scallop’s shell. Which picture below shows the
direction the scallop will move?
1. The picture above shows the directions in which water
leaves this scallop’s shell. Which picture below shows the
direction the scallop will move? D
2.
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 constant force on an object produces
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.
A.
2.
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 constant force on an object produces
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.
A.
3.
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?
The puck’s temperature changed.
B. An upward force acted on the puck.
C. The puck’s momentum remained
unchanged.
D. An opposing force acted on the puck.
A.
3.
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?
The puck’s temperature changed.
B. An upward force acted on the puck.
C. The puck’s momentum remained
unchanged.
D. An opposing force acted on the puck.
A.
4.
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.
B.
C.
D.
0.2 N
0.8 N
1.5 N
6.0 N
4.
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.
B.
C.
D.
0.2 N
0.8 N
1.5 N
6.0 N
5.
Which of these is the best description of the
action-reaction force pair when the space shuttle lifts
off from the launch pad?
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.
A.
5.
Which of these is the best description of the
action-reaction force pair when the space shuttle lifts
off from the launch pad?
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.
A.
6.
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 —
much greater mass
B. smaller amount of momentum
C. greater kinetic energy
D. smaller force applied to it
A.
6.
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 —
much greater mass
B. smaller amount of momentum
C. greater kinetic energy
D. smaller force applied to it
A.
7.
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
7.
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
8.
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.
B.
C.
D.
What goes up must come down.
For every action there is an equal and
opposite reaction.
The shape and size of an object affect air
resistance.
The acceleration due to Earth’s gravity is 9.8
m/s2.
8.
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.
B.
C.
D.
What goes up must come down.
For every action there is an equal and
opposite reaction.
The shape and size of an object affect air
resistance.
The acceleration due to Earth’s gravity is 9.8
m/s2.
9.
Which of these would cause the
gravitational force between Earth and the sun to
decrease?
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
A.
9.
Which of these would cause the
gravitational force between Earth and the sun to
decrease?
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
A.
10. An athlete sitting in a wheelchair at rest throws
a basketball forward. Since the athlete and the
wheelchair have greater mass than the basketball
has, the athlete and the wheelchair will —
move backward at a lower speed than the
basketball moves forward
B. travel the same distance as the basketball but
in the opposite direction
C. move backward at a higher speed than the
basketball moves forward
D. have the same forward momentum as the
basketball
A.
10. An athlete sitting in a wheelchair at rest throws
a basketball forward. Since the athlete and the
wheelchair have greater mass than the basketball
has, the athlete and the wheelchair will —
move backward at a lower speed than the
basketball moves forward
B. travel the same distance as the basketball but
in the opposite direction
C. move backward at a higher speed than the
basketball moves forward
D. have the same forward momentum as the
basketball
A.
11. A child jumps on a trampoline, as shown above.
Which of the following causes the child to rise in the
air?
A.
B.
C.
D.
Inertia
Mass
A reaction force
A gravitational force
11. A child jumps on a trampoline, as shown above.
Which of the following causes the child to rise in the
air?
Inertia
B. Mass
C. A reaction force
D. A gravitational force
A.
12. 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? Record and bubble in your answer
to the nearest whole number on the answer document.
12. 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? Record and bubble in your answer
to the nearest whole number on the answer document.
100 kg x 6.3 m/s = 630 kg m/s
13. How many newtons of force does a 50.0 kg deer
exert on the ground because of gravity? Record and
bubble in your answer on the answer document.
13. How many newtons of force does a 50.0 kg deer
exert on the ground because of gravity? Record and
bubble in your answer on the answer document.
50.0 kg x 9.8 m/s2 = 490 N