Cypress College PHYS 130 Homework

Physics 130, Homework CHAPTER 8-9 (A) Rotational Motion and Gravity. Due:
Read the  chapters. At the end of each chapter, study Summary of Terms and Formulas.
Answer  all Review Questions.  Try every third Exercise and Problem (i.e. 1, 4, 7, 10, ...)
Solutions are in the Library.  Print Last, First Name and date on the small Scantron in INK.  Print
your last name in BIG BLOCK  letters on the back of the Scantron.   Use a No. 2 pencil to fill out
Scantron.  Answer the following questions and turn in your Scantron only.  Choose the best
answer.

Chapter 8 Rotational Motion
1)    An upright broom is easier to balance when the heavier end is
A)  nearest your hand.
B)  highest, farthest from your hand.
C)  same either way.

2)    Centrifugal forces are an apparent reality to observers in a reference frame that is
A)  at rest.
B)  rotating.
C)  moving at constant velocity.
D)  an inertial reference frame.
E)  none of these.

3)    Consider a rotating donut-shaped space habitat where living quarters are on the inside surface farthest from the axis.  If the rotational speed of the habitat increases, the apparent weight of people inside
A)  stays the same.
B)  decreases.
C)  increases.

4)    To turn a stubborn screw, it is best to use a screwdriver that has a
A)  long handle.
B)  yellow color.
C)  wide handle.
D)  none of these.

5)    If the planet Jupiter underwent gravitational collapse, its rate of rotation about its axis would
A)  increase.
B)  stay the same.
C)  decrease.
D)  more information needed.

6)    A ring, a disk, and a solid sphere begin rolling down a hill together.  The one to reach the bottom first is the
A)  ring.
B)  sphere.
C)  disk.
D)  they all reach the bottom at the same time.
E)  not enough information is given.

7)    If you balance a broom horizontally on one finger, the center of gravity of the broom will be above your finger - closer to the bristles end than the handle end.  If you saw the broom in two pieces at that point and weigh the two parts on a scale, you'll find that the heavier part is the
A)  bristles part.
B)  handle part.
C)  both the same weight.

Chapter 9 Gravity
8)    The amount of gravitational force that acts on the space shuttle while in orbit is
A)  the same as the shuttle's weight on the earth's surface.
B)  nearly zero.
C)  almost as much as the shuttle's weight on the earth's surface.

9)    Two objects move toward each other because of gravity.  As the objects get closer and closer, the acceleration of each
A)  increases.
B)  remains constant.
C)  decreases.

10)    When the distance between two stars decreases by half, the force between them
A)  ncreases to twice as much.
B)  stays the same.
C)  increases to four times as much.
D)  decreases by one-quarter.
E)  decreases by one-half.

11)    Half way to the center of a planet of uniform density, your weight compared to at the surface would be
A)  one-quarter.
B)  one-half.
C)  three-quarters.
D)  the same as at the surface.
E)  zero.

12)    Inside a freely-falling runaway elevator, your
A)  acceleration is zero.
B)  gravitational interaction with the earth is zero.
C)  apparent weight is zero.
D)  all of these.
E)  none of these.

13)    If the sun collapsed to a black hole, the earth's gravitational attraction to it would be
A)  the same.
B)  more.
C)  less.

14)    How far must one travel to get away from the earth's gravitational field?
A)  to a region above the earth's atmosphere.
B)  to a region beyond the solar system.
C)  to a region well beyond the moon.
D)  ...forget it; you can't travel far enough.

15)    The main reason ocean tides exist is that the pull of the moon
A)  and sun are in conjunction at high tides and in opposition at low tides.
B)  is greater on oceans closer to the moon and less on oceans farther from the moon.
C)  and the sun on the oceans are in opposite directions.
D)  is greater on the earth because the moon is closer to earth.
E)  none of these.


Cypress College
Update 6/26/2003