General Physics (PH201) Summer Term 2008
Some Review Questions for Midterm Exam
Basic
Knowledge (definitions, etc…) This is fundamental, background information that
is pretty much required to be able to do well in this class. Most of this will
be new to students who have not taken a physics course before. Just memorizing
this information is not enough to do well on the tests. You must be able to
apply this knowledge in meaningful ways. See below for applications and a few
sample problems.
1) Know
basic geometry. (Formulas for areas, volumes, circumferences, etc.)
2) Know
basic algebra. (Including multiple equations with multiple unknowns.)
3) Know
basic trigonometry. (Sine, cosine, etc… What these mean; how they are used.)
4) What is a
unit? A base unit? Derived unit? Examples of each? (Know
all common examples in class.)
5) Properly
read, write, and use metric prefixes (the common ones.)
6) Use
conversion factors to correctly convert a quantity measured in one unit to
another unit.
7) What is a
dimension? What is dimensional analysis?
8) What is
the mks system? The SI system?
The cgs system? Which is used mostly in this class?
9) What is a
measurement standard? How are they determined?
10) What is
a scalar quantity? A vector quantity? Examples of each? (Know all
common examples.)
11) What is
the resultant vector? What is a component (of a vector)?
12) What
does it mean to resolve a vector into components?
13) What is
a coordinate frame?
14) What is kinematics?
15) What are
the basic kinematics equations? What do all the variables stand for?
16) What is freefall?
What is terminal speed (or terminal velocity)?
17) What is g?
What does it mean? How/when is it used? Value for g on Earth?
18) What is
a projectile? Trajectory? Range?
19) What is
true for projectiles that are fired at complimentary angles? What angle gives
the greatest range (and in what situations)?
20) What
about air resistance? What is it? Why do we ignore it? What are the
consequences of ignoring it?
21) Define
fully: distance, displacement, speed, velocity, acceleration
22)
Distinquish average versus instantaneous speed/velocity/acceleration.
23) What is
a force? What forces do we deal with in this course? (Tension, for
example.)
24) What is tension?
25) What is net
force? How is it determined? (At least two important possibilities.)
26) What
does concurrent mean? What are concurrent forces?
27) What is
a free body diagram? Why is it useful?
28) What is
a point object? What does it mean; how/why is it used? What’s the point?
29) What the
heck is inertia?
30) What are
Newton’s Three Laws? What do they mean? Be able to explain them in different
ways.
31)
Distinguish mass and weight. Define.
32) What is G?
What does it mean? How is it used? Value for G?
33) What is apparent
weight? Weightlessness? What are two ways weightlessness can be
achieved?
34) What is friction?
Distinquish between static and kinetic friction.
35) What is
the coefficient of friction? Units?
36) What is
the normal force? Direction? (What does normal mean in this context?)
37) What is
the relationship between a normal force and friction?
38) What
does equilibrium mean? How is a state of equilibrium achieved?
Applications.
These are the skills necessary to solve the basic physics problems expected of
you on the tests. The bulk of the tests will be taken from the following:
1) Be able
to correctly perform dimensional analysis. Use dimensional analysis to
determine the possible validity of an equation
2) Be able
to correctly perform unit analysis.
3) Be able
to correctly convert units of measure successfully. For example, convert m/s
into mph.
4) Be able
to correctly resolve any vector into perpendicular components.
5) Be able
to find a resultant vector of the combination of any number of vectors. Be able
to do this graphically and mathematically. Note that the mathematical solution
is most important.
6) Recognize
appropriate coordinate frames to simplify solutions to problems where the
motion is not horizontal. (Objects on inclines for example.)
7) Apply
correct kinematics equation or combination of equations to solve
one-dimensional problems.
8) Be able
to solve two-dimensional kinematics problems, especially projectile problems.
These can include projectiles fired at any angle and taking off and landing at
any level.
9) Determine
average and instantaneous velocities from a graph of position vs. time.
Determine average and instantaneous accelerations from a graph of velocity vs.
time. Be able to sketch graphs of position vs. time, velocity vs. time, and
acceleration vs. time from information given concerning motion of an object.
10) Be able
to identify all forces acting on an object (in a given situation). From this,
be able to draw a free body diagram for any given problem involving forces.
11) Be able
to correctly identify action-reaction force pairs.
12) Be able
to resolve forces at angles or on inclines into useful perpendicular components
and use these in analyzing force problems.
13) Be able
to solve problems involving Newton’s Second Law. Be able to use both Newton’s
Second Law and the basic equations of kinematics to solve dynamics problems.
These can include friction, forces at angles, objects on inclines, multiple
objects linked together, tension, etc…
14) Be able
find the normal force in any situation where it matters - on horizontal
surfaces, inclined planes,
vertical surfaces, etc...
Things that
may be helpful when preparing for this exam include, but aren’t limited to:
- Study/review past homework assignments.
- Work problems other than the
assigned suggested problems at the ends of the chapters. (Odd
problems have answers in
back of book.)
- Come to office hours with specific
questions/problems you would like to have answered.
- Email the instructor for questions
that can be answered via email.
- Study with a friend, or friends,
or an enemy even, as long as you can help each other.
Some Sample
Questions. A smattering of sample questions/problems that you may or may not
ever see on a test. These questions are only samples but are typical of tests
questions/problems.
1. Is the
earth an inertial or non-inertial reference system? Does it matter? When?
2. If you
drop a ball, the earth pulls the ball downward. What is the “reaction”?
3. A bullet
is fired from a gun. How does the force on the bullet compare to the force on
the gun? Why does the bullet travel forward with a greater acceleration than
the gun does backwards? What is the backwards motion of the gun called?
4. What are
each of the three laws also known as? Can you state them mathematically?
5. A feather
floats gently downward in the air. Why, no matter how hard a person tries,
can’t they strike that feather with 200 lbs of force? (Think Newton’s Third
Law...)
6. In lab, a
0.15 kg mass hangs over the edge of the lab table attached to a string that
runs over a pulley to a 1.5 kg lab cart sitting on a horizontal table. When
released, the mass falls downward and the cart rolls across the table. If there
is no friction anywhere, what is the acceleration of the lab cart? What is the
tension in the string? If the coefficient of static friction for the cart is
0.20, will the cart accelerate from rest?
7. A
lawnmower handle makes a 50.0 degree angle with the ground. The mower has a
mass of 20.0 kg. Does a 70.0 N force on (down) the handle result in the
speeding up or slowing down of the moving mower if the coefficient of kinetic
friction is 0.30? Find the magnitude of the acceleration.
8. Merle
pulls Earl on a sled. The rope makes a 28 degree angle with the ground. If
there is 82 N of frictional force on the sled, what force must Merle apply on
the rope if the sled is moving at constant speed?
9. Find the
speed at the end of 4 s for a 65 kg skier on a 15 degree slope if the
coefficient of kinetic friction is 0.12 and he starts from rest (with an
additional nudge to start him moving, i.e., to overcome static friction.)
10. Find the
equilibrant force if a 15.0 N acts at 25.0 degrees, a 25.0 N force acts at 125
degrees, and a
30.0 N force
acts at 220 degrees.
11. Fred and
Ed pull Zippy the Wonder Dog up the hill on a sled. The hill makes a 20.0
degree angle; Zippy and the sled together have a mass of 37 kg. The coefficient
of kinetic friction is 0.16. Ed notes with his pocket protractor that the pull
rope is making a 35 degree angle with the hill. Fred, with his Ohaus-brand
pocket scale notes that the pulling force on the rope is 75 N. What is the
resulting acceleration of Zippy and his sled?
12. A 2.0 kg
mass and a 3.0 kg mass are attached to opposite ends of a cord that passes over
a frictionless, massless pulley. What is the acceleration of the 2.0 kg mass?
What is the tension in cord?
13. A 45 kg
child climbs to the top of a slide, 3.0 m straight up. If the slide is 7 m long
(back to the ground), and there’s no friction, what is the child’s acceleration
down the slide? What will the child’s speed be at the bottom of the slide? Show
that mass doesn’t make a difference to the answer...
14. A
basketball player, 22 feet (horizontally) from the 10-foot high basket shoots
the ball. If she releases the ball 7 feet off the floor at 24 ft/s and at an
angle of 35 degrees, will the ball hit the basket? (Consider all as “point”
objects.)