Your Name:  _______________________                              PHY203

                                                                                                            Exam #1

                                    Chapters 1-3

                                                                                                            Thurs., 9/25/08

 

 

 

Lecture Time:         9 a.m             1p.m.             2p.m.       3p.m.       Honors         

 

 

 

 

 

 

 

1-10    _________________        (out of 50)

 

 

 

11       _________________        (out of 20)

 

 

 

12       _________________        (out of 30)

 

 

 

Total              _______________

 

 

 

Multiple choice answer sheet-shade in correct answers below

(one choice per problem):

 

 

 

1

 

2

 

3

 

4

 

5

 

6

 

7

 

8

 

9

 

10

 

a

 

 

 

 

 

 

 

 

 

 

 

b

 

 

 

 

 

 

 

 

 

 

 

c

 

 

 

 

 

 

 

 

 

 

 

d

 

 

 

 

 

 

 

 

 

 

 

e

 

 

 

 

 

 

 

 

 

 

 

 

 

1.  Convert 350 liters to m3:

a.      0.035 m3

b.     0.35 m3

c.      3.5 m3

d.      3.5x105 m3

e.      None of the above

 

2.  Convert 60 km/hr2 to m/s2:

a.      4.6x10-3 m/s2

b.     1.67 m/s2

c.      16.7 m/s2

d.      7.8x105 m/s2

e.      None of the above

 

3.   Add 5.5 terameters to 250 gigameters:

a.      5.5025x1012 m

b.     5.525x1012 m

c.      5.75x1012 m

d.      8.0x1012 m

e.      None of the above

 

4.  A bike rider starts from rest with an acceleration of 0.035 m/s2. Find how long it

takes the bike rider to ride 2.0 km:

a.         8.0 min.

b.        11.3 min.

c.         952 min.

d.         1905 min.

e.         None of the above

 

5.  Consider two cars approaching an intersection from different directions.  One car, traveling East, starts from rest a distance, d, from the intersection with an acceleration of 3.0 m/s2. The other car, traveling North at a constant  speed of 15 m/s, is at the same distance, d, from the intersection when the first car starts. Assuming the cars arrive at  the intersection at the same time (and crash), find the time of the crash (with t=0 the time the time the first car starts moving):

a.      5.0s

b.     7.5s

c.      10.0s

d.      20.0s

e.      None of the above

 

6.  Consider balls being dropped or thrown off a cliff on Planet 203X whose gravity is such that g = 10 m/s2 exactly:

A lead ball is dropped off a cliff.  1.5 seconds later an identical lead ball is thrown straight down from the same cliff with an initial speed of 20 m/s.   If the two balls hit the ground at the base of the cliff at the same time, find the height of the cliff:

a.           2.8m

b.          70.3m

c.           138m

d.          340m

e.          None of the above

 

 

Given the choices above, answer the following questions, 7-10:

 

7.         Given a plot of x vs. t as shown below, which of the graphs above depicts a plot of v vs. t:            a., b., c., d., or e. none of the above?

8.         Given the same plot of x vs. t as shown in #7, which of the graphs above depicts a plot of a vs. t:        a., b., c., d., or e. none of the above?

 

9.   Given a plot of velocity vs. t as shown below, which of the graphs above

depicts a plot of acceleration vs. t: a., b., c., d., or e. none of the above?

10.      Given a plot of a vs. t as shown below, which of the graphs above depicts a plot of v vs. t:            a., b., c., d., or e. none of the above?

 

 

11.  Let           A = 8i + 2j, B = 2i - 3j, C = -4i - 5j

 

a.  Sketch and clearly label the vectors A , B , and C on the above graph.

 

b.  For the vector A, find the magnitude of the vector and the angle the vector makes

with respect to the x-axis (measured from the positive x-axis in a counterclockwise

direction).

 

 

 

 

c.  For the vector C, find the magnitude of the vector and the angle the vector makes

with respect to the x-axis (measured from the positive x-axis in a counterclockwise

direction).

 

 

 

 

d.  Write the vector, D= 2A-3B+4C, in vector notation.

 

 

 

 

 

 

 

 

e. Sketch and clearly label the vector D on the above graph.

 

12.  A missile is shot in a horizontal direction from a cliff at a height of H=500m at a

fortress (not shown). The missile just clears the 200m high fortress wall at a distance of 1000m, as shown above, and eventually hits the ground at some distance past the wall. Show your work. (Note: use g = 9.81 m/s2)

 

a. Using the coordinate system above for the y-direction, calculate the time it takes for the missile to reach the wall.

 

 

 

 

 

 

b.  Calculate the initial speed of the missile.

 

 

 

 

c. Write the initial velocity vector, vo, in vector notation (using the coordinate system above).

 

 

 

d.  Calculate how far past the wall (in the x-direction) the missile will hit the ground.

 

 

 

 

 

 

 

 

e.  Calculate and write the final velocity, vf, of the projectile just before it hits the ground in vector form (using the coordinate system above).

 

  PHY203

Exam #1 Crib Sheet

Chapters 1-3

Dr = r2 – r1 (displacement)

vav = Dr/Dt                 speedav = distance/time

aav = Dv/Dt                speedinst = magnitude of vel.

vInst = dr/dt              

aInst = dv/dt

 

For constant acceleration:

xf = xo + vot + (1/2)at2

vf = vo + at

Vf2 = vo2 + 2a(xf - xo)

 

For a vector A with magnitude A and direction q (measured with respect to the x-axis):

Ax = Acos(q)

Ay = Asin(q)

A = (Ax2 + Ay2)1/2

tan(q) = Ay/Ax

 

quadratic eq. sol.:      If ax2 + bx + c = 0; then x = -b+(b2-4ac)1/2/(2a)