dynamics unit test 2010 - dmci

8/8/2019 Dynamics Unit Test 2010 - DMCI

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Physics 30S

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Name:__________________________

Dynamics Unit Test /3

Part A: Multiple Choice and Vocabulary (12 marks)

1. A 23.0 kg mass of is accelerated at + 4.50 m/s2. What is the force acting on themass?

a. 1.95 x 10 -1 Nb. +104 Nc. + 5.11 Nd. 225.4 N

2. A 72.34 kg skater accelerates to a stop with a force of - 34 .4N. What is theskaters acceleration?

a. 2.49 x 10-3 m/sb. + 2.49 x 10-3 m/sc. 4.75 x 10-1 m/sd. 2.10 m/s

3. In the absence of friction, the amount of force required to keep a 6-kg objectmoving with a constant velocity of 2 m/s is __ N.

a. 0.333 Nb. 2. 3 Nc. 12 Nd. No force is required to keep the object in motion.

4. If the net force acting upon an object is 0 N, then the object MUST ____.a. be movingb. be acceleratingc. be at restd. be moving with a constant speed in the same directione. Either c or d.


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Physics 30S

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Name:__________________________

5. An apple is thrown into the air and is moving upwards and toward the righttowards its peak. Assuming no air friction, the ball experiences a force which is_______

a. Directed upwards and to the right.b. Directed downward and to the right.c. Directed downward only.d. Directed upward only.

6. If two motionless ice skaters of different mass push each other away from oneanother, the acceleration of the heavier person will be:

a. The same as that of the lighter person because ofNewtons third law

b. Larger than that of the lighter person because of his/hergreater mass

c. Smaller than that of the lighter person because ofNewtons third and second laws

d. It is impossible to tell given only this information.7. Forces that act without touching an object are called

______________________________.

8. The quality of an object that makes it want to resist a change in motion is______________________________.

9. Newtons ______________________________ states that the acceleration ofan object is inversely proportional to its mass and directly proportional to the netforce on acting on that mass.

10._____________________________ is defined as a force that arises whentwo objects are in contact.

11. The __________________________ is always perpendicular to the contactsurface.

12.The force that keeps protons from repelling each other inside the nucleus isreferred to as the __________________________.


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Physics 30S

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Part B Concepts and Calculations

1. A tired Mr. Vincent left his cup of Tim Hortons coffee mug on his desk thismorning. Draw a free-body diagram representing all of the forces that areacting on the mug. (2 marks)

2. A mover is pushing a heavy box along a flat surface at aconstant speed of 1 m/s. Draw a free-body diagram of

the forces acting on the box and please label all forces.(4 marks)

3. While running a 100m race, Justin is able to accelerate from rest to +9 m/s overthe course of the race. What is the average horizontal force that that his legsare exerting on his body in order to accelerate his 70 kg body. (5 marks)


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Physics 30S

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Name:__________________________

4. Please draw and label all of the forces which are acting on these objects, whichare in motion. (4 marks)

a) b)

A skydiver is falling at A hesitant hamster is slidingconstant (terminal) velocity down an incline

5. Calculate the net force, as well as the acceleration of the dog in this picture. Thecombined mass of the dog and skateboard is 15 kg. (6 marks)

10 N

10 N

7 N

15 N

20


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Physics 30S

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Name:__________________________

6. An object on a flat surface experiences an applied force of 12.4N West, but alsoexperiences a frictional force of 3.6 N East. What is the acceleration of theobject if its mass is 5.0 kg. (3 marks)

7. Sketch what a position-time (d-t graph), would look like for this object. (2 marks)

BONUS QUESTION (1 mark)

Newton developed his key principles describing motion by first looking at the work of thisfamous scientist. (Please answer in the form of question).

dynamics unit test 2010 - dmci

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