Download UNIT 2 EXAM – CELL REPRODUCTION

PHYSICS EXAM
SECTION 2: MOTION & FORCE
SECTION 3: ACCELERATION & MOMENTUM
Name:_______________________________
Date:________________________
You can use your notes – 100 Points for this Test
-------------------------------------------------------------------------------------------------------------------Section 2: Motion and Force
1. What is motion?
Motion is a change in position, measured by reference points
2. What is speed?
Speed is the rate of change in position
3. What are the three types of speed? List and briefly define them.
a. Instantaneous speed - the rate of motion at any given moment
b. Constant speed - speed that does not vary
c. Average speed - total distance traveled divided by total time of travel
4. What is velocity?
Velocity is speed in a defined direction
5. What is acceleration, and how is it measured (what units)?
Acceleration is the rate of change of velocity, and it is measured in
meters per second squared
6. What is a force?
A force is a push or a pull one body exerts on another body
7. Balanced forces are _______ equal in size and __________ opposite in direction, and do not
result in a change in velocity.
8. Unbalanced forces are ____ _______ not equal in size, and result in a positive net force,
causing an object to _______ ________ change velocity.
9. What is Inertia?
Inertia is the tendency of an object to resist any change in its motion
10. Inertia is directly proportional to ______ mass, and hence the greater the ______ mass, the
more inertia.
11. What is Newton's First Law of Motion? (also called the Law of Inertia)
Objects in motion tend to remain in motion at the same velocity and objects at rest tend
to remain at rest unless acted upon by an unbalanced force
12. What is friction?
Friction is a force that opposes motion between two surfaces that are touching each other
13. The force of gravity is an attractive force between objects. The amount of gravitational force
between objects depends largely upon their ______ mass, and their ________ distance.
14. Hence, from the above two variables, which one has a proportional relationship to gravity,
and which one has an inverse relationship to gravity?
Mass has a proportional relationship to gravity, and distance has an inverse relationship
to gravity. The strength of the gravitational attractive force between two masses is
proportional to the masses and inversely proportional to the square of the distance
between them.
15. What is weight? In your brief definition, clarify the difference between weight and mass.
Weight is the force of gravity between the earth and a body on its surface. Weight is a
force, related to mass but dependent upon proximity to a large gravity well, such as the
earth.
16. What is the force of gravity on earth? (to two significant digits, in m/s2)
9.81 m/s2
Section 3: Acceleration and Momentum
Newton's Second Law of Motion states that F = ma.
17. a. define this formula, and b. state the units these variables are measured in.
a. Force = mass x acceleration
b. mass is measured in kg, acceleration is measured in m/s2, and hence force is measured
in kg per m/s2
18. All objects fall toward the earth at the same ______ __ _____________ rate of
acceleration.
19. This means that, irrespective of an objects’ mass, the force of _______ gravity is equal on all
falling objects.
20. Given the above, what factor might cause two falling objects, dropped from the same height,
to land at different times?
air resistance
21. Projectiles follow a curved path because of the earth's ____________ _____ gravitational
pull.
22. Projectiles have two types of motion that are independent of each other. List these two types
and state what they are based upon.
a. Horizontal motion, which is based on the initial velocity given to the object
b. Vertical motion, which is based on the force of gravity pulling the object toward the
earth
23. Will an object launched horizontally land on the ground at the same time as an object simply
dropped from the same height? Yes or No (circle one) Yes
24. Briefly state Newton's Third Law of Motion
To every action, there is an equal and opposite reaction.
25. What is the property of momentum, and what is it due to?
Momentum is a property any moving object has due to its mass and velocity.
----------------------------------------------------------------------------------------------------------------Extra Credit (Two Points Each)
26. What is the law of conservation of momentum?
The total amount of momentum of a group of objects does not change unless outside
forces act on them.
27. What are the two categories of energy? List and briefly define them.
a. Kinetic energy, or the energy of motion.
b. Potential energy, or stored energy.
28. What is the law of conservation of energy?
The law of conservation of energy states that energy may change forms, but it cannot be
created or destroyed.
29. A neutrino walks into a bar and asks the bartender for a pint. The electron says, "How much
do I owe you??" The bartender replies, "For you - no charge!!" Do you think this is funny?
Not really
30. Can you tell me who Schroedinger's Cat is?
On June 7 of 1935, Erwin Schroedinger wrote to Albert Einstein to congratulate him on what is
now known as the EPR paper, a famous problem in the interpretation of Quantum Mechanics.
Soon thereafter, he published what was to become one of the most celebrated paradoxes in
quantum theory: Schroedinger's Cat. A cat is placed in a box, together with a radioactive atom.
If the atom decays, and the geiger-counter detects an alpha particle, the hammer hits a flask of
prussic acid (HCN), killing the cat. The paradox lies in the clever coupling of quantum and
classical domains. Before the observer opens the box, the cat's fate is tied to the wave function of
the atom, which is itself in a superposition of decayed and undecayed states. Thus, said
Schroedinger, the cat must itself be in a superposition of dead and alive states before the
observer opens the box, ``observes'' the cat, and ``collapses'' it's wave function.
This is much more interesting if one visits the bar with the neutrino above.