TIME OF COMPLETION______________

TIME OF COMPLETION_______________ &nb= sp; NAME____SOLUTION= _________________________

<= span style=3D'font-family:"Times New Roman"'>&nb= sp; = &nb= sp; = DEPARTMENT OF NATURAL SCIENCES

PHYS 2211, Exam 3 = &nb= sp; = &nb= sp; = &nb= sp; = &nb= sp; Section 1

Version 1 &nb= sp; = &nb= sp; = &nb= sp; = &nb= sp; = November 21, 2008

Total Weight: 100 points

1. = Check your examination for completeness prior to starting. There are a total of nine (9) prob= lems on six (6) pages.

2. = Authorized references include your calculator with calculator handbook, and the Refere= nce Data Pamphlet (provided by your instructor).

3. = You will have 50 minutes to complete the examination.

4. = The total weight of the examination is 100 points.

5. = There are six (6) multiple choice and three (3) calculation problems. Work all ca= lculation problems and 5 (five) multiple choice.&nbs= p; Show all work; partial credit will be given for correct work shown.<= o:p>

6. = If you have any questions during the examination, see your instructor who will=

be located in the classroom.

7. = Start: &= nbsp; 9:00 a.m.

Stop: &= nbsp; 9:50 a.m.

&= nbsp; &nbs= p; PROBLEM

&= nbsp; &nbs= p; POINTS

&= nbsp; &nbs= p; CREDIT

&nbs= p; &= nbsp; 1-6

&nbs= p; &= nbsp; 25

&= nbsp;

&nbs= p; &= nbsp; 7

&nbs= p; &= nbsp; 25

&= nbsp;

&nbs= p; &= nbsp; 25

&= nbsp;

&nbs= p; &= nbsp; 9

&nbs= p; &= nbsp; 25

&= nbsp;

&= nbsp; &nbs= p; TOTAL

&= nbsp; &nbs= p; 100

&= nbsp; PERCENTA= GE

CIRCLE THE SINGLE BEST ANSWER FOR ALL MULTIPLE CHOICE QUESTIONS. IN MULTIPLE CHOICE QUESTIONS WHICH REQUIRE A CALCULATION SHOW WORK FOR PARTIAL CREDIT.

1. The moment of inertia of a rigid body

a.<= span style=3D'font:7.0pt "Times New Roman"'> Depends on the axis of rotation.

b.<= span style=3D'font:7.0pt "Times New Roman"'> Cannot be negative.

(5)

c.<= span style=3D'font:7.0pt "Times New Roman"'> Depends on mass distribution.<= /o:p>

d. All of the above.

2. A boy and a girl are riding on a merry-go-rou= nd which is turning at a constant rate. The boy is near the outer edge, and the girl is closer to the center= . Who has the greater linear speed?<= /span>

T= he boy.

T= he girl.

(5)

B= oth have the same non-zero translational velocity.

B= oth have zero translational velocity.

3. Angular displacement is usua= lly express in units of

a.&n= bsp; = &nb= sp;

(5)

b. Radians.

&nb= sp;

c.&n= bsp;

d.&n= bsp; &nb= sp;

4. The moment of inertia of an object that does not pass through its center of mas= s is ________________ the moment of inertia about a parallel axis through its ce= nter of mass.

a. Always less than.

b. Sometimes less than.<= /span>

(5)

c. Sometimes equal to.

d. Always= greater than.

5. True of false:

&nbs= p; a. The momentum of a heavy object is greater than that of a light object movin= g at the same speed. True=

&nbs= p; b. The momentum of a system may be conserved even when kinetic energy of the system is not. True

&nbs= p; c. For the momentum of a system to be conserved, the momenta of individual particles in the system must be conserved. False

6. The Earth moves about the Sun in an elliptical orbit. As the Earth moves closer= to the Sun, which of the following best describes the Earth-Sun system’s moment of inertia?

= a. Decreases.

= b.<= span style=3D'font:7.0pt "Times New Roman"'> Increases.

(5)

= c.<= span style=3D'font:7.0pt "Times New Roman"'> Remains constant.=

= d.<= span style=3D'font:7.0pt "Times New Roman"'> None of the above.

&n= bsp;

&nb= sp;

7. A 2.0= 0-kg block is released 4.00 m from a massless spring with a spring constant k =3D 100 N/m that is fixed along = a plane inclined at 30.0^o. The plane is rough and the coefficient of kinetic friction between the plane and the block is 0.200.

&nb= sp;

a. Find the maximum compression of the spring.

Let’s use the following notations: d = =3D 4.00 m and final compression of the spring : x_f

I also choose to measure the gravitational potential energy from the final position of the block while the spring is maximally compressed.<= /span>

&nb= sp;

Combinin= g all three equations together:

&nb= sp;

Solving = the equation:

&nb= sp;

x_f=3D 0.782 m

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b. How far up the incline will the block travel after leaving the spring?=

Let d be the distance traveled and x_i =3D 0.782 m

&nb= sp;

Combinin= g the equations:

&nb= sp;

d =3D1.55 m

&nb= sp;

8. A merry-go-round makes 24.0 revolutions in 3.00-minute interval.=

a.<= span style=3D'font:7.0pt "Times New Roman"'> What is its angular velocity in rad= /s?

b.<= span style=3D'font:7.0pt "Times New Roman"'> The merry-go–round starts to = slow down uniformly and comes to a rest after completing 6.00 revolutions. What = was its angular acceleration during that time?

c.<= span style=3D'font:7.0pt "Times New Roman"'> How long did it take to come to res= t?

t =3D 90.0 s

d.<= span style=3D'font:7.0pt "Times New Roman"'> What distance is traveled by a poin= t on the rim of merry-go-round (2.00 m from the center of rotation) as the merry-go-round comes to rest?

= <= /span>

9.Block A, with a mass of 220 g, is traveling north on a frictionless surface with a speed of 5.00 m/s. Block B, with a mass of 300 g, travels west on the same surface until it collides with block A. After the collision, the blocks move off together with a velocity of 3.13 m/s at an angle of 42.5^o to= the north of west.