Phys. 105 Quiz 2 October 31, 1997 section (circle one) 001, 003, 005, 007, 009

Print Name __________________________ Sign Name ______________________________

Fill in the top of each sheet.  Happy Halloween

The exam is closed book and closed notes.

In Part I, there are 10 multiple choice Questions.

The answers for the multiple choice Questions are to be placed on the SCANTRON form.

Use a Number 2 pencil to fill in answers on the SCANTRON form

Make sure you give only one (1) answer to each question.

If two or more answers are filled in on the SCANTRON form, the problem will be marked wrong. If you erase an answer on the SCANTRON form, make sure all traces are removed.

For Problems II and III show ALL your work. We want to give you partial credit, but this

can be done only if your work is shown.

Correct answers with unsubstantiated work on Problems II and III will receive ZERO CREDIT. Where you are required to draw motion diagrams, FBDs, etc., you MUST use a straight edge to draw straight lines.

IF YOUR STRAIGHT LINES ARE DRAWN FREEHAND, YOU WILL GET ZERO CREDIT!!!

Here are some useful equations:

S F = ma

w = mg g = 9.8 m/s2 You can take g = 10 m/s2

v = v0 + at x - x0 = v0 t + ½ at2

2a(x - x0 ) = v2 - v02 x - x0 = ½ (v + v0)t

Fk = m k N Fsmax = m s N

ar = v2/r ar = r(2p /T)2 ar = r(2p f)2

x = xo+vocosq ot vx = vocosq o

y =yo+ vosinq ot - ½ gt2 vy = vosinq o - gt
 
 
 

Note: xo = 0 and yo = 0 if you choose origin of the coordinate system at the starting point.

Phys. 105 Quiz 2 October 31, 1997 section (circle one) 001, 003, 005, 007, 009

Print Name ________________________ Sign Name __________________________

I 20 points. Put the answers to these 10 questions on your SCANTRON sheet. In addition, circle your answers on this examination sheet. Choose the answer that is closest to the given answer.



1.  As the block is sliding up the plane, its acceleration, in m/s2, is
A) 6.0 up the plane B) 6.0 down the plane C) 4.2 up the plane D) 4.2 down the plane E) 0
 
 
 
 
 


2.  The system shown remains at rest. The force of friction on the inclined block is

  1. 0 N     B.  10 N      C. 20 N        D. 30 N         E. 50 N



3.  A 0.3-kg ball is held at an angle Q from the vertical by a horizontal force F = 4 N as shown. The tension in the string supporting the weight is

  1. 3 N            B 4 N             C. 5 N             D. 6 N               E. 7 N
  

4. A heavy wooden block is dragged by a force F along a rough steel plate, as shown for two cases. The magnitude of the applied force F is the same for both cases. The normal force in (a), as compared with the normal force in (b) is:

A) the same       B) greater         C) less          D) less for some angles of the incline and greater for others      E)   less or greater, depending on the magnitude of the applied force F. 
 
 
 

The following three problems refer to the figure shown. The ball moves with negligible friction clockwise around the loop-the-loop, and leaves its track in region III.

5. At point I, the relationship between the normal force N and weight W is

A) N = W B) N < W C) N > W D) can’t determine E) none of the above

6. At point II, the relationship between the normal force N and weight W is

A) N = W B) N < W C) N > W D) can’t determine E) none of the above

7. At point III, the direction of the acceleration is best described by

A)    B)     C)      D)      E)

8. A box rests on a rough board 10 meters long. When one end of the board is slowly raised to a height of 6 meters above the other end, the box just begins to slide. The coefficient of static friction is

A) 0.1          B) 0.25        C) 0.4        D) 0.6         E) 0.75

9. The iron ball shown is being swung in a vertical circle at the end of a 2-m string. How slowly can the ball go through its top position without having the string go slack?

A) 4.5 m/s            B) 6.0 m/s           C) 9.0 m/s             D) 10 m/s              E) 12 m/s
 
 
  



10. A 0.2 kg stone is attached to a string and swung in a circle of radius 0.6 m on a horizontal and frictionless surface. If the stone makes 150 revolutions per minute, the tension on the string is:

  1. 106,000 N          B. 30 N           C. 5N             D. 1 N        E. 0.5 N
 
 
 
 
 
 

II.

Rope A, 1 m long, is attached to the horizontal cross arm at point a, and rope B, 2 m long, is attached to the vertical shaft at point b. A 5-kg ball is attached to the other ends of the ropes. The vertical shaft rotates uniformly, making 5 revolutions in 10 seconds, and the ropes and ball assume the configuration shown in the figure.

a) Draw a free-body diagram of the 5-kg body in the indicated space.

b) Find the tension in rope A.

Ans.___________________

c) Find the tension in rope B

Ans.___________________

Show your calculations here
 
 
 
 
 
 

 III.

  1. Find the ejection speed of the bomb. Ans. ________________
  2. Find the maximum height above the point B that the bomb reached. Ans. ________
  3. Find the horizontal distance C B that the bomb travels. Ans. __________________