Transcript Slide 1
Chapter 4 Chapter Resources
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Chapter 4 Image Bank
Chapter 4 Image Bank
Chapter 4 Image Bank Object Suspended by a String
Chapter 4 Image Bank Forces Exerted on the Book
Chapter 4 Image Bank Ball Tied to a String
Chapter 4 Image Bank Ball Held in Your Hand
Chapter 4 Image Bank A Stretched Rubber Band Applying a Constant Force on the Cart
Chapter 4 Image Bank The Cart’s Motion Shown in a Linear Relationship
Chapter 4 Image Bank Acceleration of Cart
Chapter 4 Image Bank Force-Acceleration Graph
Chapter 4 Image Bank Common Forces
Chapter 4 Image Bank A Table Being Pushed in Opposite Directions
Chapter 4 Image Bank Combining Forces
Chapter 4 Image Bank Types of Forces
Chapter 4 Image Bank Net Force on the Ball
Chapter 4 Image Bank A Person Stepping on a Bathroom Scale
Chapter 4 Image Bank The System in Equilibrium
Chapter 4 Image Bank Fighting Over a Toy
Chapter 4 Image Bank The Mass of a Block and a Sphere
Chapter 4 Image Bank An Elevator Accelerating Upward
Chapter 4 Image Bank Real and Apparent Weight
Chapter 4 Image Bank The Drag Force on an Object
Chapter 4 Image Bank Identifying Interaction Forces
Chapter 4 Image Bank A Soccer Ball on a Table on Earth
Chapter 4 Image Bank Earth’s Acceleration
Chapter 4 Image Bank A Suitcase on a Stationary Airport Luggage Cart
Chapter 4 Image Bank The Tension in a Rope
Chapter 4 Image Bank Tension Forces at work in a Tug-of-war
Chapter 4 Image Bank Lifting a Bucket
Chapter 4 Image Bank The Normal Force on an Object
Chapter 4 Image Bank Man on Weighing Scale
Chapter 4 Image Bank Parts of a Portable Weighing Scale
Chapter 4 Image Bank Ramon Pushing a Bed Against the Wall
Chapter 4 Image Bank A Block in Four Different Situations
Chapter 4 Image Bank The Label of a Product
Chapter 4 Image Bank Three Blocks Stacked on Top of One Another
Chapter 4 Image Bank Tug-of-war Between a Boy and a Girl Using a Massless Rope
Chapter 4 Image Bank Instrument Attached to a Weather Balloon
Chapter 4 Image Bank Two Blocks Being Pushed Against a Frictionless Force
Chapter 4 Image Bank Two Blocks Tied Together Using a Massless Rope
Chapter 4 Image Bank Three Blocks Connected with Massless Strings
Chapter 4 Image Bank Position-Time Graph of Two Cars in Motion
Chapter 4 Image Bank Standardized Test Practice (Q. 1)
Chapter 4 Image Bank Standardized Test Practice (Q. 8)
Chapter 4 Transparencies
Chapter 4 Transparencies Transparency 4-1
Chapter 4 Transparencies Transparency 4-2
Chapter 4 Transparencies Transparency 4-3
Chapter 4 Transparencies Transparency 4-4
Chapter 4 Video Clips and Animations Forces Exerted on the Book
Chapter 4 Video Clips and Animations The Rubber Band Applying a Constant Force on the Cart
Chapter 4 Video Clips and Animations Free Body Diagrams
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Chapter 4 Video Clips and Animations Apparent Weight
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Chapter 4 Video Clips and Animations Drag Force and Terminal Velocity
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Section 4.1
Chapter Summary Force and Motion
An object that experiences a push or a pull has a force exerted on it.
Forces have both direction and magnitude.
Forces may be divided into contact and field forces.
In a free-body diagram, always draw the force vectors leading away from the object, even if the force is a push.
The forces acting upon an object can be added using vector addition to find the net force.
Section 4.1
Chapter Summary Force and Motion
Newton’s second law states that the acceleration of a system equals the net force acting on it, divided by its mass.
Newton’s first law states that an object that is at rest will remain at rest, and an object that is moving will continue to move in a straight line with constant speed, if and only if the net force acting on that object is zero.
An object with no net force acting on it is in equilibrium.
Section 4.2
Chapter Summary Using Newton’s Laws
The weight of an object depends upon the acceleration due to gravity and the mass of the object.
An object’s apparent weight is the force an object experiences as a result of the contact forces acting on it, giving the object an acceleration.
An object with no apparent weight experiences weightlessness.
Section 4.2
Chapter Summary Using Newton’s Laws
The effect of drag on an object’s motion is determined by the object’s weight and its surface area.
If a falling object reaches a velocity such that the drag force is equal to the object’s weight, it maintains that velocity, called the terminal velocity.
Section 4.3
Chapter Summary Interaction Forces
All forces result from interactions between objects.
Newton’s third law states that the two forces that make up an interaction pair of forces are equal in magnitude, but opposite in direction and act on different objects.
In an interaction pair,
F
A on B does not cause
F
B on A . The two forces either exist together or not.
Section 4.3
Chapter Summary Interaction Forces
Tension is the specific name for the force exerted by a rope or string.
The normal force is a support force resulting from the contact of two objects. It is always perpendicular to the plane of contact between the two objects.
Chapter 4 Question 1 Standardized Test Practice
1.
What is the acceleration of the car described by the graph on the right?
A.
0.20 m/s 2 B.
0.40 m/s 2 C.
1.0 m/s 2 D.
2.5 m/s 2
Chapter 4 Question 2 Standardized Test Practice
2.
What distance will the car described by the above graph have traveled after 4.0 s?
A.
13 m B.
40 m C.
80 m D.
90 m
Chapter 4 Question 3 Standardized Test Practice
3.
If the car in the graph on the right maintains a constant acceleration, what will its velocity be after 10 s?
A.
10 km/h B.
25 km/h C.
90 km/h D.
120 km/h
Chapter 4 Question 4 Standardized Test Practice
4.
In a tug-of-war, 13 children, with an average mass of 30 kg each, pull westward on a rope with an average force of 150 N per child. Five parents, with an average mass of 60 kg each, pull eastward on the other end of the rope with an average force of 475 N per adult. Assuming that the whole mass accelerates together as a single entity, what is the acceleration of the system?
A.
0.62 m/s 2 E B.
2.8 m/s 2 W C.
3.4 m/s 2 E D.
6.3 m/s 2 W
Chapter 4 Question 5 Standardized Test Practice
5.
What is the weight of a 225-kg space probe on the Moon? The acceleration of gravity on the Moon is 1.62 m/s 2 .
A.
139 N B.
364 N C.
1.35
×10
3
N D.
2.21
×10 3 N
Chapter 4 Question 6 Standardized Test Practice
6.
A 45-kg child sits on a 3.2-kg tire swing. What is the tension in the rope that hangs from a tree branch?
A.
310 N B.
4.4
×10 2 N C.
4.5
×10 2 N D.
4.7
×10 2 N
Chapter 4 Question 7 Standardized Test Practice
7.
The tree branch mentioned in Question 6 sags and the child’s feet rest on the ground. If the tension in the rope is reduced to 220 N, what is the value of the normal force being exerted on the child’s feet?
A.
2.2
×10 2 N B.
2.5
×10 2 N C.
4.3
×10 2 N D.
6.9
×10 2 N
Chapter 4 Question 8 Standardized Test Practice
8.
According the graph on the right, what is the force being exerted on the 16-kg cart?
A.
4 N B.
8 N C.
16 N D.
32 N
Chapter 4 Standardized Test Practice Extended Answer 9
Draw a free-body diagram of a dog sitting on a scale in an elevator. Using words and mathematical formulas, describe what happens to the apparent weight of the dog when: the elevator accelerates upward, the elevator travels at a constant speed downward, and the elevator falls freely downward.
Chapter 4 Standardized Test Practice Test-Taking TIP Maximize Your Score
If possible, find out how your standardized test will be scored. In order to do your best, you need to know if there is a penalty for guessing, and if so, what the penalty is. If there is no random guessing penalty at all, you should always fill in an answer, even if you have not read the question.
Chapter 4 Chapter Assessment Questions Question 1
If a golf ball, a cricket ball and a bowling ball are thrown with a same force, which ball will move with a greater acceleration?
A.
Golf ball B.
Cricket ball C.
Bowling ball D.
The three balls will have equal acceleration.
Chapter 4 Chapter Assessment Questions Answer 1 Answer: B Reason:
As , the lesser the mass the greater is the acceleration. Since golf ball has least mass, it will move with greater acceleration.
Chapter 4 Chapter Assessment Questions Question 2
Jack is boating in a river applying a contact force of 30 N, in a direction opposite to the flow of water, at the same time the water is exerting a force of 30 N on the boat. In which direction will the boat move?
A.
The boat will move in the direction of the flow of water.
B.
The boat will not move at all.
C.
The boat will move back and forth within a particular distance.
D.
The boat will move in the direction opposite to the flow of water.
Chapter 4 Chapter Assessment Questions Answer 2 Answer: B Reason:
Since two equal and opposite forces are acting together, the net force is zero. Hence, the boat will not move at all.
Chapter 4 Chapter Assessment Questions Question 3
What is inertia?
A.
Force.
B.
Tendency of a body to stay only at rest. C.
Tendency of a body to move with constant acceleration.
D.
Tendency of a body to move with constant velocity.
Chapter 4 Chapter Assessment Questions Answer 3 Answer: D Reason:
Inertial of a body is the tendency of a body to stay at rest and/or to move with constant velocity, remember being at rest is simply a special case of state of constant velocity,
v
= 0 m/s.
Chapter 4 Chapter Assessment Questions Question 4
If the weight of a person on Earth is 120 N, what will his weight be on the Moon? (Gravity on Moon is six times less than the gravity on Earth.) A.
B.
C.
D.
Chapter 4 Chapter Assessment Questions Answer 4 Answer: A Reason:
Gravity on Moon is Mass of the person is (since mass = weight/
g
) Weight of person on Moon = Gravity on Moon × mass of person So, weight of the person on Moon =
Chapter 4 Chapter Assessment Questions Question 5
What happens when the
drag force
is equal to the
force of gravity
?
A.
Object comes to rest.
B.
Object moves with constant acceleration.
C.
Object moves with constant velocity.
D.
Velocity of the object increases.
Chapter 4 Chapter Assessment Questions Answer 5 Answer: C Reason:
When drag force equals the force due to gravity, the net force acting on the object is zero. As a result of which, the object moves with constant velocity, which is called terminal velocity.
Chapter 4 Chapter Assessment Questions Question 6
If a table-tennis ball, a football and a baseball are dropped in air which ball will have the greater terminal velocity?
A.
Table-tennis ball B.
Football C.
Baseball D.
All the balls will reach the terminal velocity at the same time.
Chapter 4 Chapter Assessment Questions Answer 6 Answer: C Reason:
When light objects with large surface areas are falling, the drag force has a substantial effect on their motion, and they quickly reach terminal velocity. Heavier more compact objects are not affected as much by the drag force. Baseball being heavier and more compact will have the greater terminal velocity in air.
Chapter 4 Forces in One Dimension