Niu (qn269) – HW01 – Tsoi – (58020)
1
This
printout
should
have
19
questions.
Multiplechoice questions may continue on
the next column or page – find all choices
before answering.
001
10.0 points
Highway safety engineers build soft barriers
so that cars hitting them will slow down at a
safe rate. A person wearing a safety belt can
withstand an acceleration of 300 m
/
s
2
.
How thick should barriers be to safely stop a
car that hits the barriers at 86 km
/
h? Answer
in units of m.
002
(part 1 of 3) 10.0 points
Consider the velocity curve of a one dimen
sional motion along the
x
axis.
The initial position is
x
= 10 m. The scale
on the horizontal axis is 2 s per division and
on the vertical axis 2 m/s per division.
a
b
c
time
×
(2 s) per division
velocity
×
(2 m/s) per division
The position at
t
= 4 s is given by
1.
x
= 30 m
2.
x
= 14 m
3.
x
= 18 m
4.
x
= 10 m
5.
x
= 24 m
6.
x
= 22 m
7.
x
= 12 m
8.
x
= 16 m
9.
x
= 28 m
10.
x
= 20 m
003
(part 2 of 3) 10.0 points
The average velocity
v
between 0 s and 6 s is
given by
1.
5 m
/
s
<
v
≤
6 m
/
s
2.
1 m
/
s
<
v
≤
2 m
/
s
3.
8 m
/
s
<
v
≤
9 m
/
s
4.
7 m
/
s
<
v
≤
8 m
/
s
5.
3 m
/
s
<
v
≤
4 m
/
s
6.
4 m
/
s
<
v
≤
5 m
/
s
7.
6 m
/
s
<
v
≤
7 m
/
s
8.
9 m
/
s
<
v
≤
10 m
/
s
9.
2 m
/
s
<
v
≤
3 m
/
s
10.
0 m
/
s
<
v
≤
1 m
/
s
004
(part 3 of 3) 10.0 points
The average acceleration
a
between 14 s and
16 s is given by
1.
0 m
/
s
2
<
a
≤
1 m
/
s
2
2.

3 m
/
s
2
<
a
≤ 
2 m
/
s
2
3.
3 m
/
s
2
<
a
≤
4 m
/
s
2
4.

5 m
/
s
2
<
a
≤ 
4 m
/
s
2
5.

2 m
/
s
2
<
a
≤ 
1 m
/
s
2
6.
1 m
/
s
2
<
a
≤
2 m
/
s
2
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Niu (qn269) – HW01 – Tsoi – (58020)
2
7.

1 m
/
s
2
<
a
≤
0 m
/
s
2
8.
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '09
 Staff
 Physics, Acceleration, Velocity, m/s, 1 inch

Click to edit the document details