DYNAMICS handout

 

III.    Dynamics - study of the relationship between ______________ and ________

 

            A)   Newton's Three Laws of Motion

 

1st Law      Law of ___________________

 

            "An object at rest tends to stay at ________________. 

An object in motion tends to stay in _______________ in straight line unless

            acted on by an unbalanced ___________________."

 

Another words … If a moving object has no unbalanced force on it, it would

 

__________________________________________________________________________

 

The larger the mass, the _______________________ inertia

 

2nd Law     Relationship between _____________________________

 

Applying an unbalanced force on an object causes that

 

object to ___________________________according to the equation

 

                                              a =  __   __

                                                  

 

1.                  Acceleration is ___________________ related to the force exerted on that    

           object.

                                                                                          

a

F

 

X 3

 

x 2

 

 

 

 

 

                                                        

 

2.         The acceleration a given force will produce on an object is      

 _____________ proportional to the mass of the object.

 

                        F =       10nt                                       F =       10nt

                        m =     2kg                                         m =     4kg

                        a =      5 m/s2                                   a =      ______m/s2

 

                           

a

M

 

 

x2

 

 

x2

 

 

x3

 

3.            Inertial mass (solve for m) You can calculate the mass of an object by

 

__________________________________

 

 

           

  Inertial mass   m =

 

           

 

 

4. Standard equation                F   =   ma

 

                                                         (N)                 (Kg)  (m/s 2)

 

Newton - defined - force needed to give a ____________ of mass an

 

acceleration of ___________

                       

Derived unit - A unit that comes from the_______________________________  

N = Kg m/s 2

 

                        Fundamental unit - (opposite) _________________

 

 

 

 

 

Force Questions

 

Ex1)    What is the force necessary to give a 3.0 kg mass, initially at rest, an acceleration of 5.0 m/s 2  ?

 

                                    F = ma

                                     

 

 

Ex2)    A force of 30 nt accelerates an object by 15 m/s2.  Find the objects mass.

 

                       

 

                       

 

 

Ex 3)   An unbalanced force of 100 nt acts on a 50 kg mass for 5 seconds. 

          Find the acceleration of the mass

 

                         

 

 

Ex 4)   A 10. kg cart moving with a velocity of 2.0 m/s is brought to a stop in 2.0 sec.   Find magnitude of the average force used to stop cart.

 

             

 

 

3rd Law of Motion

 

For every action there is _____________________________________________

 

 

 

 

           

 

 

A lamp applies a force of 10 N to a table. What force does the table apply on the lamp? Which direction is this force applied?

 

B)         Free Body Diagrams - diagrams that show the forces acting on an object

 

Ex1)                           

 
 

 

 

 

 

 

 

 

                                    Weight = mg                                           

 

About the Normal Force

             

(1) __________________ force supporting an object

 

(2) Always drawn _____________________to surface where 2 objects meet

 

(3) When an object is placed on a horizontal surface ________________________________

 

Ex 2)   Object on an incline plane

 

 

 

 

Ex 3)   Force on a falling object