hw3_s - homework 03 YOO HEE Due 4:00 am Question 1 chap 2...

homework 03 – YOO, HEE – Due: Jan 24 2008, 4:00 am 1
Question 1, chap 2, sect 2.
part 1 of 1 10 points
The graph below shows the velocity v as a
function of time t for an object moving in a
straight line.
t
v
0
t
Q
t
R
t
S
t
P
Which of the following graphs shows the
corresponding displacement x as a function of
time t for the same time interval?
1.
t
x
0
t
Q
t
R
t
S
t
P
2.
t
x
0
t
Q
t
R
t
S
t
P
3. None of these graphs are correct.
4.
t
x
0
t
Q
t
R
t
S
t
P
correct
5.
t
x
0
t
Q
t
R
t
S
t
P
6.
t
x
0
t
Q
t
R
t
S
t
P
7.
t
x
0
t
Q
t
R
t
S
t
P
8.
t
x
0
t
Q
t
R
t
S
t
P
9.
t
x
0
t
Q
t
R
t
S
t
P
Explanation:
The displacement is the integral of the ve-
locity with respect to time:
vectorx =
integraldisplay
vectorvdt.
Because the velocity increases linearly from
zero at first, then remains constant, then de-
creases linearly to zero, the displacement will
increase at first proportional to time squared,
then increase linearly, and then increase pro-
portional to negative time squared.
From these facts, we can obtain the correct
answer.
t
x
0
t
Q
t
R
t
S
t
P
Question 2, chap 2, sect 4.
part 1 of 5 10 points
The following 5 questions refer to a toy
car which can move to the right or left on a
horizontal surface along a straight line (the +
distance axis).
The positive direction is to the right. Dif-
ferent motions of the car are described be-
low. Choose the acceleration-time graph
which corresponds to the motion of the car
described in each statement.

homework 03 – YOO, HEE – Due: Jan 24 2008, 4:00 am 2
car
v
g
O
+
The car moves toward the right (away from
the origin), speeding up at a steady rate.