Summer Assignment Problems

Summer Assignment Selected Problems – AP Physics
Chapter 1 – Problems (from Pg. 8)
•17.
Five clocks are being tested in a laboratory. Exactly at noon, as determined by the WWV time
signal, on successive days of a week the clocks read as in the following table. Rank the five
clocks according to their relative value as good time-keepers, best to worst. Justify your choice.
Clock Sun. Mon. Tues. Wed. Thurs. Fri. Sat.
A 12:36:40 12:36:56 12:37:12 12:37:27 12:37:44 12:37:59 12:38:14
B 11:59:59 12:00:02 11:59:57 12:00:07 12:00:02 11:59:56 12:00:03
C 15:50:45 15:51:43 15:52:41 15:53:39 15:54:37 15:55:35 15:56:33
D 12:03:59 12:02:52 12:01:45 12:00:38 11:59:31 11:58:24 11:57:17
E 12:03:59 12:02:49 12:01:54 12:01:52 12:01:32 12:01:22 12:01:12
As a contrast between the old and the modern and between the large and the small, consider the
following: In old rural England 1 hide (between 100 and 120 acres) was the area of land
needed to sustain one family with a single plough for one year. (An area of 1 acre is equal to
4047 m 2 .) Also, 1 wapentake was the area of land needed by 100 such families. In quantum
physics, the cross-sectional area of a nucleus (defined in terms of the chance of a particle
53.
56.
hitting and being absorbed by it) is measured in units of barns, where 1 barn is
. (In nuclear physics jargon, if a nucleus is “large,” then shooting a particle at it is like
shooting a bullet at a barn door, which can hardly be missed.) What is the ratio of 25
wapentakes to 11 barns?
A traditional unit of length in Japan is the ken . What are the ratios of (a)
square kens to square meters and (b) cubic kens to cubic meters? What is the volume of a
cylindrical water tank of height 5.50 kens and radius 3.00 kens in (c) cubic kens and (d)
cubic meters?
The common Eastern mole, a mammal, typically has a mass of 75 g, which corresponds to
about 7.5 moles of atoms. (A mole of atoms is .) In atomic mass units (u),
what is the average mass of the atoms in the common Eastern mole?
57. An astronomical unit (AU) is equal to the average distance from Earth to the Sun, about
. A parsec (pc) is the distance at which a length of 1 AU would subtend an
angle of exactly 1 second of arc (Fig. 1-8). A light-year (ly) is the distance that light,

Summer Assignment Selected Problems – AP Physics
traveling through a vacuum with a speed of 186 000 mi/s, would cover in 1.0 year. Express
the Earth–Sun distance in (a) parsecs and (b) light-years.
Chapter 3 –Questions (From Pg. 52)
FIGURE 1-8 Problem 57.
1. Being part of the “Gators,” the University of Florida golfing team must play on a putting
green with an alligator pit. Figure 3-23 shows an overhead view of one putting challenge of the
team; an xy coordinate system is superimposed. Team members must putt from the origin to the
hole, which is at xy coordinates (8 m, 12 m), but they can putt the golf ball using only one or
more of the following displacements, one or more times:
The pit is at coordinates (8 m, 6 m). If a team member putts the ball
into or through the pit, the member is automatically transferred to
Florida State University, the arch rival. What sequence of
displacements should a team member use to avoid the pit?
5. If , does (a) , (b)
, and (c) ?
6. Describe two vectors and such that
7.
(a) and ;
(b)
(c) and .
Which of the arrangements of axes in Fig. 3-25 can be labeled “right-handed coordinate
system”? As usual, each axis label indicates the positive side of the axis.

Summer Assignment Selected Problems – AP Physics
Chapter 3 –Problems (from pg. 53)
sec. 3-4 Components of Vectors
FIGURE 3-25 Question 7.
•1. The x component of vector is −25.0 m and the y component is +40.0 m. (a) What is the
magnitude of ? (b) What is the angle between the direction of and the positive direction
of x?
•3. What are (a) the x component and (b) the y component of a vector in the xy plane if its
direction is 250° counterclockwise from the positive direction of the x axis and its magnitude is
7.3 m?
••7. A room has dimensions 3.00 m (height) × 3.70 m × 4.30 m. A fly starting at one corner flies
around, ending up at the diagonally opposite corner. (a) What is the magnitude of its
displacement? (b) Could the length of its path be less than this magnitude? (c) Greater? (d)
Equal? (e) Choose a suitable coordinate system and express the components of the displacement
vector in that system in unit-vector notation. (f) If the fly walks, what is the length of the shortest
path? (Hint: This can be answered without calculus. The room is like a box. Unfold its walls to
flatten them into a plane.)

Summer Assignment Selected Problems – AP Physics
•9. (a) In unit-vector notation, what is the sum if and
? What are the (b) magnitude and (c) direction of ?
•11. A person desires to reach a point that is 3.40 km from her present location and in a direction
that is 35.0° north of east. However, she must travel along streets that are oriented either north–
south or east–west. What is the minimum distance she could travel to reach her destination?
•13.
Two vectors are given by:
and
In unit-vector notation, find (a) , (b) , and (c) a third vector such
that .
•17. The two vectors and in Fig. 3-30 have equal magnitudes of 10.0 m and the angles
are and . Find the (a) x and (b) y components of their vector sum , (c) the
magnitude of , and (d) the angle makes with the positive direction of the x axis.
FIGURE 3-30 Problem 17.