BJU Physics Chapter 2, 3 & 4

first equation of motion

Final velocity is directly proportional to the uniform acceleration calculated from an initial velocity; v_2x = v_1x + a_x ∆t

right triangle

A triangle containing a 90° angle

second equation of motion

Displacement or position is dependent on the initial velocity, uniform acceleration, and the interval of time under consideration; d_x = v_1x ∆t + ½a(∆t)² or x₂ = x₁ + v_1x ∆t + ½a(∆t)²

acceleration (a)

The time rate of change of velocity (v); a = ∆v/∆t

What are fundamental dimensions?

space, matter and time

How many significant digits in 6.022×10²³ Pa

4

How far will a rock fall in 10. s, starting from rest? Use an order-of magnitude estimation to identify the correct choice.

490.5 m

345.6 cm + 200. cm + 6.87 cm

552.47 cm

6.77 × 10¹ m − 9.66 × 10⁻⁴ m

67.769 m

43.5 cm ×20. cm

870

position-time graph

A graph of an object's position versus time; the slope at any given point gives the object's speed

velocity-time graph

A graphical plot of velocity (usually one component) versus time; may be used to evaluate displacement and acceleration during selected time intervals; area under the curve is displacement, slope at any point is acceleration

velocity (v)

A physical quantity that requires two pieces of information in order to be completely described - a scalar value (magnitude) and a direction relative to a specified reference frame; average velocity is ∆d/∆t

vector

A physical quantity that requires two pieces of information in order to be completely described - a scalar value and a direction relative to be specified reference frame

scalar

A quantity that can be completely described with only one piece of numerical information; a number that can be positive, negative, or zero

similar triangle

A triangle whose three angles are congruent to the corresponding angles of another triangle

position vector (r)

A vector with its tail at the origin of a coordinate system and its head at the position of an object at a given time

sine θ

In a right triangle, the ratio of the length of the side opposite the acute angle θ to the length of the hypotenuse

tangent θ

In a right triangle, the ratio of the length of the side opposite the acute angle θ to the side adjacent to the angle

uniformly accelerated motion

Linear motion in which acceleration during the time interval of interest is constant; motion in which the average acceleration equals the instantaneous acceleration; free fall (neglecting air resistance) is an example of this

Is estimating as many decimals places as possible using one's best judgment a way to increase measurement certainty?

NO

component vector

One of the two (or three) vectors parallel to the designated coordinate axes that can be summed to produce the vector being analyzed in two (or three) dimensions

magnitude

The absolute value of the measure of a quantity; the size of a measurement without regard to its direction or sign

dynamics

The branch of mechanics that mathematically describes the causes of motion (forces)

reference direction

The direction from which a vector angle is measured; usually the direction of the positive x-axis or the direction to the North Pole, depending on the situation

vector angle (θ)

The direction of a vector measured from a specified reference direction; expressed in degrees or radians

displacement (d)

The distance and direction between an object's position at one time and its position at a later time; a vector.

reference angle (α)

The positive acute angle between a vector and its horizontal component vector

difference vector

The resultant of a vector subtraction operation; the difference of two velocities would be represented by ∆v

free fall

The state of falling toward the earth or other planetary object under the influence of gravity only

mechanics

The study of motion of macroscopic objects; the study of how (kinematics) and why (dynamics) things move

resultant

The vector sum or difference of two or more vectors

metric system

What is the formal name for the set of standards that defines the fundamental units of measurement used primarily in science?

An example of a derived unit is the ____________

density

The speedometer on your car measures

instantaneous speed

Tools that permit more exacting measurements and human senses are called ______

instruments

an example of a two dimensional geometric object other than a plane is a(n) ________________.

is a 1-D object

Which is a possible unit for acceleration?

m/s

The measure of an objects tendency to resist a change in the motion is that objects__________________

mass

Significant digits apply only to _______data

measured

what unit is fundamental?

meter

How many significant digits in 100 cm/1 m

na

what are characteristics of a good measurement standard?

not affected by environmental variables universally accepted measured with a high level of precision

The exactness of data is determined by _____ with which it was measured

precision

The SI unit for angle measure is the ____________

radiant

The SI unit for time is the _________________

seconds

Certain digits in a measurement based on the instrument scale calibration and one estimated digit are collectively called_____________.

significant digit

Scalar quantity is

speed

The equations of linear motion apply only if

system acceleration is constant

The slope of a two -dimensional position-time graph gives

velocity

A ball is dropped from a 80.0 m building. What is the ball's velocity after 3.00 s? Use an order-of- magnitude estimation to identify the correct choice.

⁻29.4 m/s

distance

How far an object travels during a given trip; a scalar

cosine θ

In a right triangle, the ratio of the length of the side adjacent to the acute angle θ to the length of the hypotenuse

kinematics

The branch of mechanics that describes how systems move, without addressing what causes the motion

third equation of motion

The one-dimensional displacement or position of a system is proportional to the difference of the squares of its final and initial velocities during an interval and is inversely proportional to its uniform acceleration; d_x = ((v_2x)² - (v_1x)²) / 2a_x or x₂ = x₁ + ((v_2x)² - (v_1x)²) / 2a_x

scalar component

The scalar value of a component vector

Which change results in zero acceleration of a system

a change in only the direction of velocity

The last or least significant digit in a measurement is ____

estimated

What is the SI unit for mass?

kilogram

_____digits in a measurement are always significant

non-zero

The results of an unspecified measurement was 1.558 63 units. If the accepted value for the quantity is 2.000 units, how would you characterize the result?

not accurate, but precise

The area beneath a velocity-time graph with a given time interval gives

the distance covered by the system during that interval

A microvolt is equal to

10⁻⁶ V.

234m/18s

13

How many significant digits in 0.0004 cm

1