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SPH 3U TEST REVIEW: DYNAMICS

 

 

TEST DATE: Wednesday, Oct 16

 

DYNAMICS TEST OUTLINE:

A. Newton’s Three Laws:

Memorize each law and be prepared to answer question(s) applying each law to some situation such as a car crash or amusement park ride.

 

B. Problems: resolving two forces which are (a) linear, (b) at right angles to each other

 

C. Bodies in Equilibrium Problem: resolving three forces which are in equilibrium (ΣF = 0) forming a closed triangle

 

D. Basic friction problems using Ff =μ FN

 

E. Problems combining uniform acceleration, friction, and Newton’s Second Law.

 


        F. A basic problem involving the Law of Universal Gravitation

 

 

1.                  A child is pulling a 10 kg wagon along with a force of 20 N [east] on a road with a frictional force of 5 N. Calculate:

acceleration of the wagon. (3 marks)     1.5 m/s2 [E]

 

 

 

2.                 

 

omit

 

 

 

3.                  Two people are having a tug-of-war. Person "Y" is pulling 200 N [north] nand person "X" is pulling at 100 N [east.] Their ropes are attached to to mass "A" which is resting on a frictionless tabletop. Mass A is 20 kg. Find the acceleration of mass A. (5 marks)     ________

 

 

 

 

4.                  Three children are pulling on ropes as described below. Child A is pulling at 40 N [east], child B is pulling at 30 N [north] Calculate the magnitude and direction of force. AC@ if the forces are balanced. (ie: the system is not moving)

 

 

 

 

 

 

5.                  For each of Newton’s First Law, Newton=s Second Law and Newton=s Third Law:

 

State the law. Describe an example of each law which you would experience as a passenger in any amusement park ride (such as the tilt-a whirl or a roller coaster) (12 marks)     For the test, be sure to memorize Newton's Laws (all postulatles).   Check out the section on "Newton's Laws" in chapter 1 of your text for more information on the applications of Newton's Laws.

 

 

5. A 1.0 kg cart is pushed along with an initial velocity of 2.0 m/s. It it released and it coasts to a stop in 3.0 s. What is the coefficient of friction between the two surfaces?     coefficient of friction is 0.068

 

6. A 0.5 kg object is pushed along horizontally with an applied force of 10 N.   If the object starts from rest and accelerates to 8.0 m/s in 6 seconds, what is the coefficient of friction between the two surfaces?     coefficient of friction is 1.9 (note: this is a really large value)