Your Name: _______________________ PHY203
Exam
#1
Chapters
1-3
Fri.,
2/08/08
Lecture Time: 1p.m. 2p.m.
1-10 _________________ (out
of 60)
11 _________________ (out
of 40)
Total _______________
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1. 1
acre is 43560 square feet in area. How many square centimeters is that?
a. 46.7
cm2
b. 1.43x103
cm2
c. 1.33x106
cm2
d. 4.05x107
cm2
e. None
of the above
2.
Convert 30 m/s to km/h:
a. 1.8
km/h
b. 8.33
km/h
c. 1.08x102
km/h
d. 5.0x102
km/h
e. None
of the above
3.
How many meters is 56 megakm in correct scientific notation?
a. 5.6x103
m
b. 5.6x106
m
c. 5.6x109
m
d. 5.6x1010
m
e. None
of the above
4.
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 m/s2. The other car, traveling North at a
constant speed of 10 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 distance d:
a.
1.5m
b. 25.8m
c. 33.3m
d.
66.7m
e. None
of the above
5.
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. 2 seconds later an identical lead ball
is thrown straight down from the same cliff with an initial speed of 30
m/s. Find the time measured
from when the first ball was released at which the balls are exactly
side-by-side:
a. 1.6 sec.
b. 2.0 sec.
c. 4.0 sec.
d. 10.0 sec.
e. None of
the above
6. For the above graph, find the
instantaneous acceleration at position B.:
a. -20.0
m/s2
b. -10.0
m/s2
c. -5.0
m/s2
d. 0
m/s2
e. None
of the above
7. For the above graph, find the
instantaneous acceleration at position D.:
a. -20.0
m/s2
b. -10.0
m/s2
c. -5.0
m/s2
d. 0
m/s2
e. None
of the above
8. For the above graph, find the average
acceleration from A to E.:
a. -1.25
m/s2
b. -0.8
m/s2
c. 0
m/s2
d. 1.25
m/s2
e. None
of the above
For problems 9 and 10,
Let A = -5i + 9j, B = 3i - 10j, C = -2A + 4B
9.
Find the magnitude of the vector A:
a. 4.0
b. 7.5
c. 14.0
d. 106
e. None
of the above
10.
Find the angle that vector B
makes with the positive x-axis (measured in a
counterclockwise direction from the positive
x-axis):
a. 16.7o
b. 73.3o
c. 287o
d. 343o
e. None
of the above
11.
A motorcycle stunt rider rides up a ramp with an initial speed of 20
m/s. The rider wants to clear a barrier with a height of 7.5m with respect to
the top of the ramp at a distance, D, from the end of the ramp, as shown below.
Show your work. (Note: use g
= 9.81 m/s2).
a.
Assuming the rider just clears
the barrier, calculate the y component of the rider’s initial velocity
using the coordinate system above.
b. Assuming the rider just clears the barrier, calculate the angle the ramp makes with horizontal and the x component of the initial velocity.
c.
Assuming the rider just clears the barrier, calculate the distance, D,
from the beginning of the ramp the barrier must have been placed.
d.
Assuming the rider just clears the barrier, write the velocity, vb, of the rider just as the rider crosses over the
barrier in vector form using the above coordinate system.
PHY203
Exam
#1
Crib
Sheet
Chapters
1-3
speedAV
= (total distance traveled)/Dt
Dr = r2 – r1 (displacement)
vAV
= Dr/Dt
aAV
= Dv/Dt
vInst
= dr/dt
aInst
= dv/dt
For constant acceleration:
xf = xo
+ vot + (1/2)at2
vf = vo
+ at
Vf2 =
vo2 + 2a(xf - xo)
use g = 9.81 m/s2, the acceleration due to gravity, unless
otherwise directed
For a vector A with magnitude A and direction q
(measured counterclockwise 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)
