Monday, November 28, 2016

Activity 42a - Forces in Motion Problem Set #1

Activity 40.10 - Read these pages  on gravitational mass and the conclusions from the lab.

Pick up a paper copy of Forces in Motion Problem Set #1, and complete it, (you can ignore questions "18. f" and "18. g").

When you are done check your answers here.

Activity 38: Newton's 3rd Law - Picking the right system

Lecture Slides

38.10 : Example problems

Activity 42: Accelerating with Newton Lab

Read the Accelerating with Newton Lab, page 86 - > 95 in this document.  Notice this lab has three procedures.  Each procedure has its own analysis section.  You can write a single conclusion paragraph but it should contain your conclusions from each procedure.

Here is a link to the experiment logger-pro template file

Use this template for your lab write-up. You simple need to follow the procedures outlined, answer the questions in the analysis sections and write a conclusion.

Tuesday, November 22, 2016

Activity 41: Calculating Tension

Activity 58.10

Pick up a paper copy of this handout on calculating tension.

Activity 58.20

Pick up a paper copy of these tension problems  When done check your answers here.

Thursday, November 17, 2016

Wednesday, November 16, 2016

Activity 33 : Forces in 2D PS #3

Activity 47.10

Pick up a copy and complete these two seminar problems.

When done check your answers here.

Activity 47.20

Pick up a copy of "Force Be with You Problem Set 3".

When you are done,  done check your answers here.

Activity 47.30

Pick up a paper copy of this activity and complete it.

Put your answer in this form.

Monday, November 14, 2016

Activity 32: Forces in 2D PS #2

Pick up, and review,  a paper of this write-up on "Force Diagrams and Equilibrium"

Pick up a paper  copy of "Force Vectors in 2D Problem Set #2" and complete the problems.

When done check your answers here.

Activity 31: Introduction to Forces in Equilibrium

Activity 43.20 - Forces in Equilibrium

Newton's first law of motion is often stated as
An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.  
So an object that is not moving, or an object that is moving at a constant velocity will not change its motion unless an unbalanced force is applied to it.  The term unbalanced force is simply a way of stating that if I add up all the forces on an object then that total force  is not equal to zero.  If however the forces on an object are in balance then the net force is zero and the object's motion or lack of motion will not change.


An object is said to be in linear equilibrium if the net force on the object is equal to zero.  Another way to state this is,  the net force on an object which is not accelerating must be equal to zero.

Forcenet = 0 if an object is in equilibrium ( it is not accelerating).

Newton's 2nd law is often stated as Fnet = Mass X Acceleration.

As you can see from this equation if an object's acceleration is equal to zero (it is in equilibrium) then its Fnet = 0.

If the net force on an object is zero it then follows that:

  • All of the forces in the horizontal direction must add up to zero.
  • All of the forces in the vertical direction must add up to zero.
You may wonder why we care about the summation of an object's horizontal and vertical vectors adding up to zero.  The can be summarized as:

  • The main technique to adding vectors is to add their horizontal and vertical components together.  If we know an object is in equilibrium, then we know the summation of its horizontal and vertical components must also equal zero.  Otherwise it would be accelerating either horizontally or vertically or both.

Watch this video to help you understand how you can use the concept of forces in equilibrium to calculate the forces on an object.

Activity 43.30 Vector Addition Review

Answer to following problems 5,6,7,9 &10:

Activity 43.40 Vector Components

Pick up a paper copy of this worksheet.  Review the drawings on the first page and answer the questions on page 168.   Check your answers on the last page of the document.

Activity 30A: Mystery Mass Lab

Monday, November 7, 2016

Assignment 29 - Introduction to Newton's Laws

Force  - Any push or pull on an object

Dynamics  - Study of forces that cause objects or systems to move.

Mass - A measure of the amount of stuff in an object.  The more mass an object has,  the more it is resistant to a change in its motion. An object's resistance to change in motion is called inertia and this inertia is directly proportional to an object's mass. 

Newton's First Law of Motion

A body at rest remains at rest, or, if in motion will, remains in motion at a constant velocity unless acted on by an external force.  

The acceleration of a system is directly proportional to and in the same direction sat the net external force acting on a system, and inversely proportional to its mass.

              Fnet = ma  

Units of force: 1 Newton is the force necessary to to acceleration 1kg at a rate of 1 m/s/s.

            1N = 1kg m/s/s

Weight is a force where g is the acceleration due to gravity.

             w = mg

The weight of a 1 kg object is :
                    w = 1kg x 9.8 m/s/s = 9.8N

Assignment 29.10

Types of forces
Pick up a paper copy and review the list of "contact" and "at a distance forces".  Pick up a paper copy and review the list of forces.

Free Body Diagrams
Pick up a copy of this document on free body diagrams and answer it's question.  When done, review your answers here.

Assignment 29.20

Read pages 127 - 136 , sections 4.1, 4.2, 4.3 in the textbook

Answer questions 
1,2,3 , 5 on page 161 in the textbook.  Review your answers here.