Topics:
• Motion and Newton’s first law
•
•
•
•
•
What is a force?
Identifying forces
Newton’s second law
Free‐body diagrams
Newton’s third law
N t ’ thi d l
Sample q p question:
These ice boats sail across the ice at great speeds. What gets the boats moving in the first place? What keeps them from going even faster?
Slide 4-1
What Causes Motion?
In the absence of any forces acting on it, an object will continue moving forever. Motion needs no “cause.”
Slide 4-8
Seat Belts: An Application of Newton’s First Law
Slide 4-9
What Is a Force?
A force... force ... is a push or pull.
... is a vector.
... acts on an object. object
... requires an agent. agent
... is a contact force or a long-range force.
Slide 4-10
Force Vectors
Slide 4-11
→
A Short Catalog of Forces: Weight w
→
Slide 4-12
→
Spring Force Fsp
Slide 4-13
Tension Force T
Slide 4-14
Normal Force n
Slide 4-15
→
Friction fk and fs
Slide 4-16
Drag D and Thrust Fthrust
Slide 4-17
Identifying Forces – The free body diagram
Slide 4-18
Example
A block is dragged uphill by a rope Identify all rope. forces acting on the block.
Slide 4-19
Example
Block A hangs from the ceiling by a rope Another block B hangs rope. from A. Identify the forces acting on A.
Slide 4-20
Exercise
A ball hanging from the ceiling by a string is pulled ball, string, back and released. Identify the forces acting on it just after its release.
Slide 4-21
Newton’s Second Law
Slide 4-22
Example
An elevator, lifted by a cable, is going up at a steady speed elevator cable speed. • Identify the forces acting on the elevator.
• Is T greater than, equal to, or less than w? Or is there not enough i f h information t t ll? ti to tell?
Slide 4-23
Free-Body Diagrams
Slide 4-24
Newton’s Third Law
Slide 4-25
Identifying Forces for Interacting Objects
Slide 4-26
Checking Understanding
10-year-old
10 year old Sarah stands on a skateboard Her older brother skateboard. Jack starts pushing her backward and she starts speeding up.
The force of Jack on Sarah is
A. greater than the force of Sarah on Jack.
B. equal to than the force of Sarah on Jack.
C. less th th f
C l than the force of Sarah on Jack. fS h
J k
Slide 4-27
Answer
10-year-old
10 year old Sarah stands on a skateboard Her older brother skateboard. Jack starts pushing her backward and she starts speeding up.
The force of Jack on Sarah is
B. equal to than the force of Sarah on Jack.
Slide 4-28
Quiz
1.
1 What is a “net force? net force?”
Slide 4-2
Quiz
2.
2 List at least three of the steps used to identify the forces acting on an object.
A.
A Identify “the system” and “the environment ” environment.” B. Draw a picture of the situation.
C. Draw a closed curve around the system.
D. Locate every point on th b
D L t i t the boundary of thi curve where th d f this h the environment touches the system.
E. Name and label each contact force acting on the object.
F. N
F Name and l b l each l d label h long-range f force acting on the object. ti th bj t
Slide 4-3
Quiz
3.
3 Which of these is not a force discussed?
A. The tension force.
C. The orthogonal force.
B. The normal force.
D. The thrust force.
Slide 4-4
Reading Quiz
4.
4 An action/reaction pair of forces
A. point in the same direction.
B. act on the same object.
C.
C are always long range forces. long-range forces
D. act on two different objects.
Slide 4-6
You May Also Find These Documents Helpful
-
When t = 13, (t − 12)(t + 4) = 17 which is greater than zero t < 12 is not is the solution set…
- 1376 Words
- 6 Pages
Good Essays -
chen (azc96) – Assignment 6 - Electricity – schultz – (WVSPR2011APB01) This print-out should have 20 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 (part 1 of 2) 10.0 points An object with a charge 3 C and a mass 0.4 kg accelerates from rest to a speed of 19 m/s.…
- 984 Words
- 4 Pages
Satisfactory Essays -
What is the name of the vein beginning at the apex of the heartand ascending in the anterior interventricular groove with theanterior interventricular artery?…
- 911 Words
- 4 Pages
Good Essays -
1. During normal quiet breathing, about ______ ml of air moves into and out of the lungs with each breath. a.…
- 1362 Words
- 6 Pages
Satisfactory Essays -
Two guy wires run from the top of a pole 2.6 m tall that supports a volleyball net. The…
- 432 Words
- 2 Pages
Good Essays -
Exercise 8: Chemical and Physical Processes of Digestion: Activity 2: Exploring Amylase Substrate Specificity Lab Report Pre-lab Quiz Results You scored 100% by answering 5 out of 5 questions correctly. 1. Which of the following is true of enzymes and substrates? You correctly answered: c. Enzymes are specific about the substrates they can act upon. 2. Which of the following is/are reducing sugars? You correctly answered: e. both glucose and maltose 3. Cellulose and starch are both You correctly answered: e. polymers of glucose and polysaccharides. 4. Proteins and peptides are formed by joining amino acids with a special type of covalent bond called a peptide bond. Which of the following enzymes do you think would be specific for a peptide bond? You correctly answered: c. peptidase 5. The Benedict's assay tests for the presence of You correctly answered: c. reducing sugar.…
- 521 Words
- 3 Pages
Satisfactory Essays -
2. If you double the current through an inductor, the energy stored in the associated magnetic field increases by a factor of _____.…
- 934 Words
- 4 Pages
Powerful Essays -
|True or False: A solution containing glucose will diffuse faster through a 200 MWCO membrane if it|True |…
- 1242 Words
- 5 Pages
Good Essays -
How does this set of data compare to the data you recorded for Activity 2? The MRV is 3075 and the breathing is not as strong.…
- 1006 Words
- 5 Pages
Good Essays -
Q1. Figure 1 shows a solid cylindrical steel rod of length = 2.0 m and diameter D = 2.0 cm. What will be increase in its length when m = 80 kg block is attached to its bottom end? (Young's modulus of steel = 1.9 × 1011 Pa) Fig#…
- 3155 Words
- 13 Pages
Satisfactory Essays -
4. Put the following in order from smallest to largest molecular weight: glucose, sodium chloride, albumin, and urea.…
- 924 Words
- 4 Pages
Good Essays -
4a) In order to determine the instantaneous rate of change of a function using the methods discussed in this lesson, we would use the formula where h will approach 0, and the closer it gets to 0 the more accurate our answer will be.…
- 319 Words
- 4 Pages
Satisfactory Essays -
Exercise 2: Skeletal Muscle Physiology: Activity 3: The Effect of Stimulus Frequency on Skeletal Muscle Contraction Lab Report Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1. During a single twitch of a skeletal muscle You correctly answered: b. maximal force is never achieved. 2. When a skeletal muscle is repetitively stimulated, twitches can overlap each other and result in a stronger muscle contraction than a stand-alone twitch. This phenomenon is known as You correctly answered: c. wave summation. 3. Wave summation is achieved by You correctly answered: a. increasing the stimulus frequency (the rate of stimulus delivery to the muscle). 4. Wave summation increases the force produced in the muscle. Another way to increase the force produced by a muscle is to You correctly answered: d. increase the number of activated motor units.…
- 1052 Words
- 5 Pages
Good Essays -
Exercise 1: Cell Transport Mechanisms and Permeability: Activity 1: Simulating Dialysis (Simple Diffusion) Lab Report…
- 435 Words
- 2 Pages
Satisfactory Essays -
The experiment was about the resolution of vector quantities using different methods or techniques. Among those are the Parallelogram, Polygon, and the Analytical or Component methods. Using each method, it was found out that Component method is the most accurate as its approach is purely theoretical, that is, all other physical factors are neglected leaving only the appropriate ones to be calculated. In addition, properties of these quantities such as associativity and commutativity of the addition operation were also explored.…
- 1219 Words
- 5 Pages
Better Essays