Unformatted text preview: Homework 1 — sai — _ p 1 This print—out should have 33 questions.
Multiple—choice questions may continue on
the next column or page — ﬁnd all choices
before answering. 001 (part 1 of 2) 10.0 points While John is traveling along a straight inter-
state highway, he notices that the mile marker
reads 241 km. John travels until he reaches
the 148 km marker and then retraces his path
to the 172 km marker. What is John’s resultant displacement from
the 241 km marker?
Correct answer: —69 km. Explanation: Let the initial position be so = a = 241 km,
the second position b = 148 km, and his ﬁnal
position sf = c = 172 km. Thus As=sf—SO=172km—241km2—69km 002 (part 2 of 2) 10.0 points
How far has he traveled?
Correct answer: 117 km. Explanation:
The distance traveled is given by d: |b—a|+|c—b|
= |148 km — 241 kml + |172 km — 148 km|
2117 km 003 (part 1 of 2) 10.0 points
Consider a moving object whose position a:
is plotted as a function of the time t on the
following ﬁgure: ll 2 4 6 Clearly, the object moved in different ways
during the time intervals denoted I, II and III
on the ﬁgure. During these three intervals, when was the
object’s speed highest? Caution: Do not
confuse the speed with the velocity. 1. During interval I. 2. Same speed during each of the three in-
tervals. 3. During interval III. correct
4. During interval II. 5. During intervals II and III (same speed
during those two intervals). Explanation:
The velocity V is the slope of the a:(t) curve;
the magnitude 1) = |v| of this slope is the speed. Looking at the picture we see that
the curve is steepest (in absolute magnitude)
during the interval III and that is when the
object had the highest speed. 004 (part 2 of 2) 10.0 points
During which interval(s) did the object’s ve—
locity remain constant?
1. During each of the three intervals. cor-
2. During interval I only.
3. During none of the three intervals. 4. During interval III only. 5. During interval II only. Explanation:
For each of the three intervals I, II or III,
the 11:05) curve is linear, so its slope — the velocity V — is constant during each interval.
Between the intervals, the velocity did change
in a rather abrupt manner — but it did remain
constant during each interval. 005 (part 1 of 6) 5.0 points
Consider the following graph of motion. ...
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- Spring '08