# Physics Exam Review

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### In science, a theory is

a synthesis of a large body of well-tested knowledge

### The scientific method is most effective in

gaining, organizing, and applying new knowledge

hypothesis

mechanics

thermodynamics

by experiments

### In the steps of the scientific method, what is the next step after formulating and objectively testing hypotheses?

interpreting results

electromagnetism

length and time

kilogram

1 second

### How does a scientist reduce the frequency of human error and minimize a lack of accuracy?

take repeated measurements
use the same method of measurement
maintain instruments in good working order

precise

### Calculate the following, and express the answer in scientific notation with the correct number of significant figures: 21.4+15+17.17+4.003

5.8 x 10^1
(the number with the lowest amount of sig figs is 15, which has two sig figs so the answer must have 2 sig figs)

1.1

### What is not a step that is part of the scientific method?

Repeat the experiments until the answers match the predictions (doesn't have to match your predictions)

### A hypothesis

an educated guess that has yet to be proved by experiment

### A theory is

a synthesis of a large collection of information including well-tested guesses

### One difference between a hypothesis and a theory is that a hypothesis

is a guess that has not been well tested, whereas a theory is a synthesis of well-tested guesses

### What is an example of a scientific hypothesis?

Atoms are the smallest particles of matter that exist (If it is a valid hypothesis, there must be a test for proving that it is wrong)

### To test a scientific hypothesis you would

set up many experiments and look at the results

four

### A human hair is approximately 50 micrometers in diameter. Express this is meters.

5.0 x 10^-5 m
(50micrometers x 1x10^-6m/1micrometer = 50 x 10^6 = 5.0 x10^-5)

law

### physics is the most basic science because

it is about the nature of basic things like forces, energy, and motion

### Listening to the radio involves what area of physics?

vibrations and wave phenomena

Kelvin

4.52 x 10^-7 m

### The law of inertia states that an object

-will continue moving at the same velocity unless an outside force acts on it
-will continue moving in a straight line unless an outside force acts on it
-that is not moving will never move unless a force acts on it
-at rest will remain at rest unless acted on by an outside force

### The law of inertia applies to

both moving and nonmoving objects

### A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly. The reason this can be done is that

the milk carton has inertia

less

inertia

weight

mass

### According to Newton's law of inertia, a railroad in motion should continue going forever even if its engine is turned off. We never observe this because railroad trains

always have forces that oppose their motion

one

5.52x10^5 kg

### How does acceleration of an object change in relation to the applied force? It is

directly proportional

It doubles

It halves

8.0 N

### If shopping cart A has five times more mass in it than shopping cart B and the two cars are pushed with equal forces, you can expect the acceleration of shopping cart A to be

1/5 times that of shopping cart B

108 N

force

### What statements describe force?

-force causes objects to start moving
-force causes objects to stop moving
-force causes objects to change direction

kg x m/s^2

0.22 m/s^2

0.0 m/s

### Suppose you take a trip that covers 180km and takes 3 hours to make. Your average speed is

60 km/h
(x/t=speed)
(180km/3h=60km/h)

### A school bus takes 0.530h to reach the school from your house. If the average velocity is 19km/h to the east, what is the displacement?

(average velocity=change in x/ change in t)
(19=change in x/ 0.530)
19x.530=10.07 km
convert to m (x 1000) = 10,070 m to the east

### Speed is

-a measure of how fast something is moving
-always measured in terms of a unit of distance divided by a unit of time
-the distance covered per unit time

### Acceleration is defined as

the rate of change of velocity

10 seconds

### The motion of a ball on an inclined plane is described by the equation: change in x=1/2a(change in time)^2. Which of the following must have a value of zero?

initial velocity (vi)

### Suppose an object is in free fall. Each second the object falls

a larger distance than in the second before

### Objects that are falling toward Earth in free fall move

faster and faster

### Would a leaf or a stone fall with greater acceleration in a vacuum?

they would accelerate at the same rate

### A baseball catcher throws a ball vertically upward and catches it in the same spot as it returns to the mitt. At what point in the ball's path does it experience zero velocity and nonzero acceleration at the same time?

at the top of its path

### At the instant a ball is thrown horizontally with a large force, an identical ball is dropped from the same height. Which ball hits the ground first?

Neither. They both hit the ground at the same time.

### Identify the following quantities as scalar or vector: the mass of an object, the number of leaves on a tree, wind velocity.

scalar, scalar, vector

vector

### A ball thrown in the air will never go as far as physics ideally would predict because

air friction slows the ball

scalar

### At what part of a path does a projectile have minimum speed?

At the top of its path

45 degrees

5 units

velocity

### A projectile is fired horizontally in a vacuum. The projectile maintains its horizontal component of speed because it

is not acted on by any horizontal forces

440 N

25 N

a parabola

### In a coordinate system, the magnitude of the x component of a vector and theta, the angle between the vector and x-axis, are known. The magnitude of the vector equals the x component

divided by the cosine of theta

kinetic friction

### When representing velocity as a vector,

-the direction of the arrow shows the direction of motion
-the length of the arrow represents the speed
-the length of the arrow is drawn to a suitable scale

### The gravitational force b/w two massive spheres

-is always an attraction
-depends on how massive they are
-depends inversely on the square of the distance b/w them

increases

25 N

120 N

4.0 N

Example: