The questions and problems are in the following sections:

  Basics of Forces                 (answers to this section)    (back to the top)

1.  What is a force?  Is it a scalar or a vector quantity?

2.  What are the three main classifications of forces?

3.  What is a field force?

4.  The unit of force in the MKS system of units is the _______________ .

5.  Is it possible for an object somewhere in the universe to have no forces whatsoever acting on it?
     Explain.

Gravitational Force        (answers to this section)    (back to the top)

1.  In response to a test question a student answers that “Gravity is 9.8 N”.
     What is wrong with this answer?

2.  Suppose you want to make some money in the gold market by buying gold at one altitude
    and selling it for the same dollars per Newton at another altitude.  Is “Buy low, sell high”
    a good sales strategy?

3.  What are the factors which determine the force of gravity between two objects?

4.  What is the force of gravity of your 5.6 Kg cat on the ground?

5.  If 1.0 Kg weighs 2.2 lb on the earth, where can you buy a Newton burger?
 

 Force Diagrams        (answers to this section)    (back to the top)

1.  What is the purpose of drawing a force diagram?

2.  What is a Normal force?

3.  Draw a force diagram for each of the following situations:
            a)  You and your cousin are pulling in opposite directions on a sweatshirt.
                 You are pulling harder. (2 forces)

            b)  A box sits on a table.  (2 forces)

            c)  You help your friend push their car in the parking lot.  (4 forces)

            d)  You pull on the rope of a sled to slide it along the ground.
                 The rope makes an angle of 50° with the horizontal.  (3 forces)

            e)  A sky diver is falling with a constant velocity.  (2 forces)

            f)  Your wet jeans are hanging in the middle of the clothesline.  (3 forces)
 

Addition of Forces                     (answers to this section)    (back to the top)

1.  What is a component?

2.  What does it mean to “resolve a force into its components”?

3.  Outline the steps of adding vectors by resolution.

4.  Two forces, one 5 N and the other 8 N, act concurrently on a box.
     What are the minimum and maximum values for the net force on the box?

5.  Calculate the net force on the object in the situations below:

6. 
     In pulling a wagon you pull on the handle with a force of 200 N.
     If the handle makes an angle of 55° with the horizontal, what are
     the vertical and horizontal components of the applied force?
 
 
 
 
 
 

7. 
     In pulling a nail the hammer exerts a force on the nail as  shown
     at the right.  What are the vertical and horizontal components of
     the force on the nail?
 
 
 
 
 
 
 

8.  Calculate the net force for each of the following force diagrams:

9.  Two soccer players each kick the ball at the same time.  If the two forces on the ball
     are 400 N[N30°E] and 600 N [W20°S].  What is the net force on the ball?
 

Static Equilibrium                      (answers to this section)    (back to the top)

1.  What is meant by the term equilibrium?

2.  What is the only condition necessary for static equilibrium to occur?

3.  Is it possible for a wire, stretched between two poles, to be perfectly horizontal?
     Explain.

4. 
     Given the three forces acting on an object as shown at the right,
     determine if the object is in equilibrium.
 
 
 
 
 
 
 
 
 
 
 

5.  You are holding the string of a helium balloon.  If the balloon has a mass of 0.05 Kg and
     the upward force on the balloon is 2.0 N, what force do you have to apply to the string to
     hold the balloon stationary?
 
 

Friction                       (answers to this section)    (back to the top)

1.  What is friction?

2.  Give two examples of when friction is a hindrance and two examples when it is beneficial.

3.  What are two types of friction?

4.  Which of the types of friction would be involved in each of the following situations?
         a) sitting in a chair                           b) pushing a box across the floor

         c) using a pencil eraser                     d)  walking across the floor

5.  What does a coefficient of friction represent?

6.  If a 30 N force is required to start a 5.0 Kg box sliding across the floor, what is the
     coefficient of static friction?

7.  To keep the box in #6 moving it takes 20 N or 60 N, but you can’t remember which.
     Which one is more likely correct?  Explain how you would figure it out.

8.  Why do we talk of a maximum force of static friction, but not a maximum force of
     kinetic friction?

9.  What is the effect of changing each of the following on the magnitude of the frictional force?
            a) surface area in contact

            b) surface type

            c) Normal force