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PROBLEM SET #1
Day 2 Homework Problems Due Tuesday
1.
HELICOPTER FLYABOUT
JonesChilders/3ed Problem 2.1 (p.55) A helicopter leaves its base and travels 20.0 km
north.
After a brief stop, it flies 35.7 km south, pauses briefly and then flies 17.0 km north.
Finally it flies 6.0 km south and
lands.
At the end of the trip, what is the displacement of the helicopter from its base?
[
4.7 km south of the base
]
2.
OBJECT POSITION vs. TIME JonesChilders/3ed Problem 2.5 (P.56)
Fig 2.31 (p A56) shows positiontime graph for
three different objects A, B, and C.
(a) Which object is farthest from the origin at time
t
=0? (b) Which object is at rest at
time
t
= 2.5 s?
(c) Which object moves the greatest distance away from the origin?
(d) How far from the origin is object
C
at
t
= 2.0 s?
(e) Which object is farthest from the origin at
t
= 3.0 s? (f) Where is object
B
at 1.5 s?
[ (a)
C
; (b)
A
; (c)
C
; (d)
0 m
; (e)
A
; (f)
2 m
]
3.
GRAPHICAL SITUATIONS
JonesChilders/3ed Problem 2.16 (p.56) Which of the displacementtime graphs in
Fig. 2.32
(p.A56) corresponds to each of the physical situations listed? (a) a ball rolled along the floor toward the origin, (b) a book at
rest on a table, (c) a ball rolling along the floor away from the origin hits a wall and bounces straight back, (d) a ball rolling
away from the origin at a constant speed, (e) a ball rolled along the floor toward a wall at the origin, the ball then rebounds,
and (f) an object rolling toward the origin that suddenly stops.
[ (a)
B
; (b)
D
; (c)
C
; (d)
A
; (e)
E
; (f)
F
]
4.
CAR SPEED/TIME JonesChilders/3ed Problem 2.26 (p.56)
You are driving a car with initial speed v
o
.
At time
t
= 0, you
begin to increase your speed at a constant rate.
Twenty seconds later you are traveling at a speed of 80 km/h.
At
t
= 60 s you
are traveling at a speed of 140 km/h.
(a) What was your initial speed
v
o
?
(b) What was your speed at
t
= 40 s?
Use a
graphical method to arrive at the answers.
[ (a)
V
o
= 50 km/h
; (b)
v
40
= 110 km/h
]
5.
AVERAGE VELOCITY
Urone/College Problem 2.13 (p.52)
A football quarterback runs 15.0 m straight down the
playing field in 2.50 s.
He is hit and pushed 3.00 m straight back in 1.75 s.
He breaks the tackle and runs straight forward
another 21.0 m in 5.20 s.
Calculate his average velocity for each of the three intervals and for the entire motion.
JonesChilders/3ed Problem 2.70 (p.60) Starting from rest, you move with a constant acceleration of 2.0 ft/s
2
for 12 s and then
move with a constant acceleration of 2.0 ft/s
2
for another 12 s.
(a) What is your maximum speed attained?
(b) How far do
you go during the whole trip?
(c) What is your average speed?
[ (a)
24 ft/s
; (b)
288 ft
; (c)
12 ft/s
]
6.
SWAN TAKEOFF Urone/College (p.53) Problem 2.30
A swan on a lake gets airborne by flapping its wings and running
on top of the water.
(a) if the swan must reach a velocity of 6.00 m/s to take off and it accelerates from rest at an average rate
of 0.350 m/s
2
, how far will it travel before becoming airborne?
(b) How long does this take?
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 Spring '08
 Akgun
 Physics, Work

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