Physics Chapter 3 Test:

Position- Time Graph

A graph of an object's position versus time

Velocity- time graph

A graphical plot of velocity (usually one component) versus time; may be used to evaluate displacement and accelerations during selected time intervals

Vector

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

Yes, although in some cases (running in a straight line), distance and displacement can be equal

Does distance often differs from the object's displacement?

Scalar

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

- 4.o km - 0.0 km

A student lives 2.0 km from his school. If he walks to school, turns around, and walks back home, what distance has he walked? What was his final displacement?

straight

A velocity-time graph has a ______ line.

Vector

Average velocity -- scalar or vector?

Vector

Change in position -- scalar or vector?

Magnitude

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

Average speed in that time interval

The absolute value of the slope of any time interval on a position-time graph gives the object's ____

difference vector

The resultant of a vector subtraction operation

forward or backward

The sign go the velocity (slope) tells us if the object is moving ____ or _____, up or down, etc.

Vf = Vi + a(t)

Write the first equation of motion

d = vi (t) + 1/2a(t)²

Write the second equation of motion

d = vf²-vi²/2a

Write the third equation of motion

The instantaneous velocity vector

What vector has a magnitude equal to the instantaneous speed?

zero

A ball is thrown straight up in the air and falls down to the found. When the ball reaches its highest point (the instant before it changes direction and begins to fall) it velocity is_____

Vector

Acceleration -- scalar or vector?

Scalar Quantity

Any quantity that includes a number (with or without units only is a

Vector Quantity

Any quantity that includes both a magnitude (#) and a direction (can be a sin or a word) is called a

Vector quantities

Are vector or scalar quantities usually represented by bold variables?

Scalar

Change in time -- scalar or vector?

Vector

Change in velocity -- scalar or vector?

The motion is constant

Describe the motion of an object if its velocity-time graph is horizontal

(bold) d -- displacement |d| and (italicized) d -- magnitude of d, or distance

Discuss the differences, if any, between the one-dimensional quantities (bold) d, |d|, and (italicized) d

Vector

Displacement -- scalar or vector?

The average speed is the ratio of the distance traveled |x₂-x₁| over an interval of time (t₂-t₁) v=|x₂-x₁|/(t₂-t₁)

How would you determine the average speed of a trip to Grandma's house?

Scalar

Distance traveled -- scalar or vector?

The smaller the interval, the better the estimate because you measure the instantaneous speed at a given point by calculating the average speed of a small interval containing that point

How does increasing the number of data points on a position-time graph improve your ability to estimate instantaneous velocity at any point on the curve?

Position-time graph

If you graph the ordered pairs (t,x) for an object's position and time, what kind of graph is this?

-9.81m/s squared

In free fall, the acceleration is always

Scalar

Instantaneous speed -- scalar or vector?

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

Uniformly accelerated motion

Motion in which the acceleration of an object is constant

meter/seconds

Si unit for velocity

Kinematics

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

Dynamics

The branch of mechanics that mathematically describes the causes of motion

Displacement

The distance and direction between an object's position at one time and its position at a later time; in oscillatory motion, the distance and direction of the system from its equilibrium position

b

The slope of a position- time curve represents a- distance b- velocity c- displacement d- acceleration

d

The slope of a velocity- Time curve represents a- distance b- velocity c- displacement d- acceleration

Instantaneous speed

The speed of an object at a particular given time at that specific instant

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

Velocity

The time rate of change in position in a specified direction

acceleration

The time rate of change of velocity

False. Displacement is positive only when the object has moved right (or up) from its initial position and it always give us both a number and directional information

True or False: Displacement is positive only when the object has moved left (or down) from its initial position.

False. Distance is always positive and it cannot give us information about the direction of movement

True or False: Distance can be positive or negative.

False. When working in 1 dimension at a time, represent vector quantities with italicized variables and subscript

True or False: When working in 1 dimension at a time, represent scalar quantities with bold variables and subscript.

True

True or False: Without a starting point (reference point, point of origin), we cannot prove that something has change position

False. Acceleration due to gravity is nearly constant at the earth's surface and is considered to be in the negative y-direction (pointing in the downward direction)

True or False: acceleration due to gravity is nearly constant at the earth's surface and is considered to be in the negative y-direction (pointing in the upward direction)

True

True or false: If speed is changing in an interval around that particular time, it isn't necessarily equal to the average speed on that interval and could be less than, greater than, or equal to the average speed for the interval

True

True or false: One dimension motion is represented on a number line

Valid for uniformly accelerated motion

Under what condition(s) is the first equation of motion valid?

Size of vehicle, initial speed, reaction time of the driver, road conditions (shape of road, surface material, and objects or substances on the surface)

What are some factors that affect stopping distance?

It describes how objects move

What does the study of kinematics describe?

Free fall

What is one common form of uniform acceleration?

Fundamental SI Unit: mole Unit Symbol: mol Formula Symbol: n

What is the Fundamental SI Unit for Amount of Substance?

Fundamental SI Unit: kelvin Unit Symbol: K Formula Symbol: T

What is the Fundamental SI Unit for Thermodynamic Temperature?

Fundamental SI Unit: kilogram Unit Symbol: kg Formula Symbol: m

What is the Fundamental SI Unit for mass?

Fundamental SI Unit: meter Unit Symbol: m Formula Symbol: d, r, s, l

What is the Fundamental SI notations for length?

Fundamental SI Unit: second Unit Symbol: s Formula Symbol: t

What is the Fundamental SI notations for time?

Object's displacement

What is the area under a velocity-time graph, bounded by a specific time interval, numerically equal to?

Average velocity

What is the displacement divided by the time interval called?

s=|x₂-x₁|+|x₃-x₂|

What is the formula for distance?

d=x₃-x₁

What is the formula for total/overall displacement?

The acceleration of an object

What kind of kinematic information is provided by the slope of a velocity-time graph?

Time interval, position, average acceleration, initial velocity, and initial position

What quantities must be known in order to find the displacement of an object using the second equation of motion?

Third equation of motion

Which equation of motion should you use if you do not know the elapsed time of an object's motion, assuming the necessary quantities are known?

a-

Which of the follow is a scalar quantity? a- distance b- velocity c- displacement d- acceleration

m/s squared

si unit for acceleration

displacement

the net change in position

Av. Velocity: V= x₂-x₁/ t₂-t₁: V= 25m-15m/ 8s-4s V= 10m/ 4s V= 5m/2s V= 2.5m/s V= 3m/s

use the data in the chart below to find the average velocity of an object over the interval t=4s to t-8s Time(s): Position(m) 0 5 2 8 4 15 6 20 8 25