CST ReviewForce
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Forces
Force Graphic Organizer
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Special Forces Graphic Organizer
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Cornell NotesTitle: Buoyancy
Questions Notes (Answers)
II. Buoyancy is the force of a liquid pushing up on an object.A. Buoyant force balances the force of gravity when an
object floats.
Question 2:What are buoyant
forces?
Buoyant Force of water pushes up.
Force of Gravity pushes down.
B. Weight is the pull of gravity on an object.
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Cornell NotesTitle: Buoyancy
Questions Notes (Answers)
Question 3:What determines the
strength (magnitude) of buoyant force?
III. The buoyant force is equal to the weight of liquid an object displaces (pushes out of the way).
A. The weight of the displaced liquid is the same as the weight of the object under the liquid.
B. The part of the object above the liquid DOES NOT MATTER.
Buoyant Force
Weight of Displaced
Water
Study
Cornell NotesTitle: Buoyancy
Questions Notes (Answers)
C. When an object is flat buoyancy is greater because it displaces more liquid. Buoyant force pushes up against a larger surface area.
Buoyant Forces of liquid push up.
Question 3:What determines the
strength (magnitude) of buoyant force?
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CST Review Questions
How is force described?II. Force has a strength
(magnitude) and a direction.
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How do forces add and subtract?A. Forces pushing or pulling in
the same direction add.
+
These forces add.
1 N right
1 N right
How do forces add and subtract?B. Forces pushing or pulling in
opposite directions subtract.
These forces subtract so the box doesn’t move.
_1 N right 1 N left
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.5cm = 2N
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3.0 cm ?
0.5 cm = 2N
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3.0 cm 12N
0.5 cm = 2N
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3.0 cm 12N
3.5 cm ?
0.5 cm = 2N
CST Review Questions
0.5 cm = 2N
3.0 cm 12N
3.5 cm 14N
CST Review Questions
.5cm = 2N
3.0 cm = 12N3.5 cm = 14 N
CST Review Questions
.5cm = 2N
3.0 cm = 12N3.5 cm = 14 N
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CST Review Questions
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______________________
What will make you have to push harder?
CST Review Questions
What will make you have to push harder?
CST Review Questions
What will make you have to push harder?
less friction?
CST Review Questions
What will make you have to push harder?
mass ?
VIII. When an object has more mass, it requires a greater force to make it move.
How does mass affect force?
500 N Right
Books = 800 kg
5 N Right
Leaves = 8 kg
A. If something is heavier, you have to push harder to move it.
How does mass affect force?
Mass of Feathers = 1 kg
Mass of Bricks = 1000 kg
2000 N Right
2 N Right
Distance moved = 5 feet
CST Review Questions
What will make you have to push harder?
harder or easier to push?
CST Review Questions
What will make you have to push harder?
easier to push
harder to push
CST Review Questions
What will make you have to push harder?
less friction?
easier to push
harder to push
XII. Friction is a force which slows down or stops an object’s motion.
What is Friction?
50 N Right
Force of friction of the wheels on the road 20 N Left
Force of the Boy pedaling his bicycle forward.
A. Friction always goes in the opposite direction of the force causing the motion.
What is Friction?
40 N Right 190 N Left
Friction slowing down motion
Force causing motion
B. Friction is caused by objects or materials rubbing against each other.
What is Friction?
Friction of Air rubbing against an
airplane.Friction of wheels on the
road
Friction of metal on snow.
Friction of hands rubbing
together.
CST Review Questions
What will make you have to push harder?
harder or easier to push?
easier to push
harder to push
CST Review Questions
What will make you have to push harder?
easier to push
harder to push
easier to push
easier to push
CST Review Questions
What will make you have to push harder?
harder to push
CST Review Questions
What will make you have to push harder?
CST Review Questions
CST Review Questions
Buoyant Forces
Consider This
XI. Buoyancy is the force of a liquid pushing up on an object.
What are buoyant forces?
Buoyant Force of water pushes up.
A. Buoyant force is equal to gravity when an object floats.
What are buoyant forces?
Buoyant Force of water pushes up.
Force of Gravity pushes down.
A. Buoyant force is equal to gravity when an object floats.
What are buoyant forces?
Buoyant Force of water pushes up.
Force of Gravity pushes down.
B. When an object is flat, Buoyancy is greater because the liquid pushes up against a larger surface area.
What are buoyant forces?
Buoyant Forces of liquid push up.
Force
Review
Think-Group-Share1. THINK: Read the question and THINK
about the answer.
2. GROUP: Discuss the answer with your teammates and agree on the correct answer.
3. SHARE your answers by writing them on the magnetic slate and holding them up.
Think-Group-Share
What is force?
Think-Group-Share
What is force?
a push or pull
How is force described?I. Force is a push or pull.
Think-Group-Share
What does force change?
A. the mass of an object
B. the motion of an object
C. the volume of an object
Think-Group-Share
What does force change?
A. the mass of an object
B. the motion of an object
C. the volume of an object
What is force?B. Force changes the motion of something
by changing its speed or direction.
Think-Group-Share
Force is measured in
A. Grams
B. Meters
C. Newtons
D. Liters
Think-Group-Share
Force is measured in
A. Grams
B. Meters
C. Newtons
D. Liters
How is force described?B. Force strength is measured in Newtons (N) (after Isaac Newton).
Think-Group-Share
What 2 things does force have?
A. magnitude and direction
B. size and shape
C. strength and shape
Think-Group-Share
What 2 things does force have?
A. magnitude and direction
B. size and shape
C. strength and shape
How is force described?II. Force has a strength
(magnitude) and a direction.
Think-Group-Share
A weight lifter raises his barbells straight up with a force of 30 Newtons. How would you describe the force?
Think-Group-Share
A weight lifter raises his barbells straight up with a force of 30 Newtons. How would you describe the force?
30 N Up
Think-Group-Share
What do forces in the same direction do?
A. subtract
B. cancel each other
C. add
Think-Group-Share
What do forces in the same direction do?
A. subtract
B. cancel each other
C. add
How do forces add and subtract?A. Forces pushing or pulling in
the same direction add.
+
These forces add.
1 N right
1 N right
Think-Group-Share
What do forces in opposite directions do?
A. subtract
B. cancel each other
C. add
Think-Group-Share
What do forces in opposite directions do?
A. subtract
B. cancel each other
C. add
How do forces add and subtract?B. Forces pushing or pulling in
opposite directions subtract.
Opposite forces subtract.
_1 N right1 N left
What is the force? Will the rope move?
Think-Group-Share
The force left after all forces have been added and subtracted is called
A. final force
B. net force
C. resultant force
Think-Group-Share
The force left after all forces have been added and subtracted is called
A. final force
B. net force
C. resultant force
What is net force?IV. The force left after all forces
have been added and subtracted is the net force.
=
These forces subtract.
_Zero Net force
1 N right 1 N left
Think-Group-Share
A boy pushes a cart with a force of 3 N right. Another boy pushes the same cart with a force of 1 N left. What is the net force on the cart?
Think-Group-Share
A boy pushes a cart with a force of 3 N right. Another boy pushes the same cart with a force of 1 N left. What is the net force on the cart?
3 N right - 1 N left = 2 N right
Think-Group-Share
A man pushes a car with a force of 10 N right. Another man helps him push the car with a force of 9 N right. What is the net force on the car?
Think-Group-Share
A man pushes a car with a force of 10 N right. Another man helps him push the car with a force of 9 N right. What is the net force on the car?10 N right + 9 N right = 19 N right
Think-Group-Share
When opposite forces on an object are equal, the forces are
A. balanced
B. unbalanced
Think-Group-Share
When opposite forces on an object are equal, the forces are
A. balanced
B. unbalanced
What are balanced forces?V. When the opposite forces on an object
are equal, the forces are balanced.
Balanced Forces
=1 N right 1 N left
Think-Group-Share
When opposite forces on an object are NOT equal, the forces are
A. balanced
B. unbalanced
Think-Group-Share
When opposite forces on an object are NOT equal, the forces are
A. balanced
B. unbalanced
What are unbalanced forces?VI. When the opposite forces on an
object are not equal, the forces are unbalanced.
Unbalanced Forces
1 N right
1 N left
2 Newtons of force 1 Newton of force
1 N right
Think-Group-Share
When forces on an object are balanced, the object
A. does not move
B. moves
C. changes form
Think-Group-Share
When forces on an object are balanced, the object
A. does not move
B. moves
C. changes form
What are balanced forces?B. When the forces are balanced, the
object does not move. (Its motion does not change).
Balanced Forces Net Force = 0
=1 N right 1 N left
Net force = 0
Think-Group-Share
When forces on an object are unbalanced, the object
A. does not move
B. changes form
C. changes its motion
Think-Group-Share
When forces on an object are unbalanced, the object
A. does not move
B. changes form
C. changes its motion
What are unbalanced forces?B. Unbalanced forces cause an object
to change its direction or motion (speed up or slow down).
=
Objects move because of unbalanced forces
1 N right
1 N right
1 N right
Think-Group-Share
A boy pulls a wagon with a force of 35 N left. The wind pushes the wagon with a force of 20 N right. Are the forces balanced or unbalanced?
Think-Group-Share
A boy pulls a wagon with a force of 35 N left. The wind pushes the wagon with a force of 20 N right. Are the forces balanced or unbalanced?
unbalanced
Think-Group-Share
A girl pulls on a rope with a force of 15N left. Her friend pulls on the rope with a force of 15 N right. Are the forces balanced or unbalanced?
balanced
Think-Group-Share
A girl pulls on a rope with a force of 15N left. Her friend pulls on the rope with a force of 15 N right. Are the forces balanced or unbalanced?
balanced
Think-Group-Share
Friction is the force A. of objects rubbing against each other
B. which pulls objects together
C. which changes the shape of objects until it is removed.
D. of liquids pushing up on an object.
Think-Group-Share
Friction is the force A. of objects rubbing against each other
B. which pulls objects together
C. which changes the shape of objects until it is removed.
D. of liquids pushing up on an object.
B. Friction is caused by objects or materials rubbing against each other.
What is Friction?
Friction of Air rubbing against an
airplane.Friction of wheels on the
road
Friction of metal on snow.
Friction of hands rubbing
together.
Think-Group-Share
Friction
A. Goes in the same direction as the motion of the object.
B. Goes in the opposite direction of the motion of the object.
C. Has nothing to do with the motion of the object.
Think-Group-Share
Friction
A. Goes in the same direction as the motion of the object.
B. Goes in the opposite direction of the motion of the object.
C. Has nothing to do with the motion of the object.
B. Friction always goes in the opposite direction of the force causing the motion.
What is Friction?
40 N Right 190 N Left
Friction slowing down motion
Force causing motion
Think-Group-Share
A girl pedals her bike forward with a force of 20N. The wind pushes her forward with a force of 10N. The friction on her wheels exerts a force of 5N backwards. What is the net force?
Think-Group-Share
A girl pedals her bike forward with a force of 20N. The wind pushes her forward with a force of 10N. The friction on her wheels exerts a force of 5N backwards. What is the net force?
20N Forward
10N Forward
20N forward + 10N forward – 5N backwards = 25N forward
5N Backwards
Think-Group-Share
Gravity is the force A. of objects rubbing against each other
B. which pulls objects together
C. which changes the shape of objects until it is removed.
D. of liquids pushing up on an object.
Think-Group-Share
Gravity is the force A. of objects rubbing against each other
B. which pulls objects together
C. which changes the shape of objects until it is removed.
D. of liquids pushing up on an object.
III. Gravity is the force that pulls objects toward each other.
What is gravity?
Think-Group-Share
Gravity
A. Compresses and stretches objects.
B. makes objects fall down.
C. slows the motion of objects.
D. makes objects float.
Think-Group-Share
Gravity
A. Compresses and stretches objects.
B. makes objects fall down.
C. slows the motion of objects.
D. makes objects float.
B. Objects fall down because the Earth’s gravity pulls them down.
What is gravity?
GRAVITY
Earth’s gravity is a force pulling objects down toward the center of the Earth.
Think-Group-Share
Objects with greater mass
A. have more gravity.
B. have less gravity.
C. have no gravity.
Think-Group-Share
Objects with greater mass
A. have more gravity.
B. have less gravity.
C. have no gravity.
How does the Sun hold the solar system together?
A. Objects with bigger mass, exert a greater force of gravity on other objects.
How does the Sun hold the solar system together?
B. The Sun’s gravity is extremely strong because its mass is EXTREMELY large.
Newton’s 2nd Law says: greater mass = greater gravity.
Think-Group-Share
Gravity gives stars and planets
A. more mass.
B. less mass.
C. their shapes.
D. greater energy.
Think-Group-Share
Gravity gives stars and planets
A. more mass.
B. less mass.
C. their shapes.
D. greater energy.
C. Gravity give stars, planets, and the solar system their shapes.
What is gravity?
Think-Group-Share
Elastic Force is the force A. of objects rubbing against each other
B. which pulls objects together
C. which changes the shape of objects until it is removed.
D. of liquids pushing up on an object.
Think-Group-Share
Elastic Force is the force A. of objects rubbing against each other
B. which pulls objects together
C. which changes the shape of objects until it is removed.
D. of liquids pushing up on an object.
IX. Elastic forces change the shape of an object. But when the force is removed, the object regains its shape.
What are elastic forces?
Leaves = 8 kg
10 N Up & Left
Think-Group-Share
Friction
A. Compresses and stretches objects.
B. makes objects fall down.
C. slows the motion of objects.
D. makes objects float.
Think-Group-Share
Friction
A. Compresses and stretches objects.
B. makes objects fall down.
C. slows the motion of objects.
D. makes objects float.
Friction is a force that slows down or stops an object’s motion.
What is Friction?
50 N Right
Force of friction of the wheels on the road 20 N Left
Force of the Boy pedaling his bicycle forward.
Think-Group-Share
Elastic Force
A. Compresses and stretches objects.
B. makes objects fall down.
C. slows the motion of objects.
D. makes objects float.
Think-Group-Share
Elastic Force
A. Compresses and stretches objects.
B. makes objects fall down.
C. slows the motion of objects.
D. makes objects float.
A. Some elastic forces stretch the object.
What are elastic forces?
10 N Up & Left
10 N Up & Left
B. Some elastic forces squeeze or compress the object.
What are elastic forces?
2 N Down
2 N Right 2 N Left
2 N Down
2 N Up
Think-Group-Share
Elastic Forces that squeeze an object are called
A. friction
B. tension.
C. compression.
D. gravity.
Think-Group-Share
Elastic Forces that squeeze an object are called
A. friction
B. tension.
C. compression.
D. gravity.
C. Elastic forces that squeeze are called compression.
What are elastic forces?
2 N Down
2 N Right 2 N Left
2 N Down
2 N Up
Think-Group-Share
Elastic Forces that stretch an object are called
A. friction
B. tension.
C. compression.
D. gravity.
Think-Group-Share
Elastic Forces that stretch an object are called
A. friction
B. tension.
C. compression.
D. gravity.
What are elastic forces?
D. Elastic forces that stretch an object are called tension.
Think-Group-Share
Buoyancy is the force A. of objects rubbing against each other
B. which pulls objects together
C. which changes the shape of objects until it is removed.
D. of a liquid or gas pushing up on an object.
Think-Group-Share
Buoyancy is the force A. of objects rubbing against each other
B. which pulls objects together
C. which changes the shape of objects until it is removed.
D. of a liquid or gas pushing up on an object.
XI. Buoyancy is the force of a liquid or gas pushing up on an object.
What are buoyant forces?
Buoyant Force of water pushes up.
Think-Group-Share
Buoyancy
A. Compresses and stretches objects.
B. makes objects fall down.
C. slows the motion of objects.
D. makes objects float.
Think-Group-Share
Buoyancy
A. Compresses and stretches objects.
B. makes objects fall down.
C. slows the motion of objects.
D. makes objects float.
A. Buoyancy makes objects float.What are buoyant forces?
Buoyant Force of water pushes up.
Think-Group-Share
Buoyant force is
A. equal to the weight of the object.
B. equal to the weight of the liquid displaced by the object.
Think-Group-Share
Buoyant force is
A. equal to the weight of the object.
B. equal to the weight of the liquid displaced by the object.
III. The buoyant force is equal to the weight of liquid an object displaces (pushes out of the way).
What are buoyant forces?
Buoyant Force
Weight of Displaced
Water
Draw this diagram.
Think-Group-Share
Objects with greater mass
A. need no force to move
B. need less force to move
C. need more force to move
Think-Group-Share
Objects with greater mass
A. need no force to move
B. need less force to move
C. need more force to move
Think-Group-Share
Objects with less mass
A. need no force to move
B. need less force to move
C. need more force to move
Think-Group-Share
Objects with less mass
A. need no force to move
B. need less force to move
C. need more force to move
VIII. When an object has more mass, it requires a greater force to make it move.
How does mass affect force?
500 N Right
Books = 800 kg
5 N Right
Leaves = 8 kg
Special Forces Practice Problems
A box has a mass of 325 kg. Another box has a mass of 95kg. Which box will need a greater force to lift it?
325 kg 95
kg
Special Forces Practice Problems
The box with the greater mass needs more force to lift it.
325 kg
95 kg
A box has a mass of 325 kg. Another box has a mass of 95kg. Which box will need a greater force to lift it?
The 325 kg box.