Physics Chapter 2 (and a little Chapter 1)

instantaneous position

The position of an object at any particular instant in time

position

The separation between an object and the origin; it can be either positive or negative

slope

The steepness of a line on a graph, equal to its vertical change divided by its horizontal change.

delta means change

know the Greek letter delta ∆ and what it means when is precedes a variable

displacement

A change in position having both magnitude and direction; is equal to the final position minus the initial position

precision

A characteristic of a measured value describing the degree of exactness of a measurement

accuracy

A characteristic of a measured value that describes how well the results of a measurement agree with the "real" value, which is the accepted value; as measured by competent experimenters

position-time graph

A graph that can be used to determine an object's velocity and position, as well as where and when two objects meet, by plotting the time data on a horizontal axis and the position data on a vertical axis

instantaneous velocity

A measure of motion that tells the speed and direction of an object at a specific instant in time

distance

A scalar quantity that describes how far an object is from the origin

motion diagram

A series of images showing the positions of a moving object taken at regular (equal) time intervals

particle model

A simplified version of a motion diagram in which the moving object is replaced by a series of single points

coordinate system

A system used to describe motion that gives the zero point location of the variable being studied and the direction in which the values of the variable increase

resultant

A vector that results from the sum of two other vectors; it always points from the first vector's tail to the last vector's tip

significant digits

All the valid digits in a measurement, the number of which indicates the measurement's precision

Speed is a scalar quantity that refers to "how fast an object is moving." Speed can be thought of as the rate at which an object covers distance. A fast-moving object has a high speed and covers a relatively large distance in a short amount of time. Contrast this to a slow-moving object that has a low speed; it covers a relatively small amount of distance in the same amount of time. An object with no movement at all has a zero speed. Velocity is a vector quantity that refers to "the rate at which an object changes its position." So in addition to speed, it also measures direction. If your velocity is -5 mph, you are traveling backwards at a speed of 5 mph

Explain the difference between velocity and speed

The slope of a position vs time graph gives you average velocity. The slope of a velocity vs time graph gives you acceleration

Explain what the slope of a line on a graph tells you

Significant figures tell us how exact and accurate the number/value is: 100 g-has only one significant figure, Because this digit is in the "hundreds" place, this measurement is only accurate to the nearest 100 grams. 100. g-has three significant figures, Because the last significant figure is in the "ones" place, the measurement is accurate to the nearest gram

Explain why the use of significant digits is important

average speed

How fast an object is moving; is the absolute value of the slope of an object's position-time graph

vector

Quantities, such as position, that have both magnitude and direction

scalar

Quantities, such as temperature or distance, that are just numbers without any direction

nano: 10^-9 micro: 10^-6 milli:10^-3 centi: 10^-2 deci: 10^-1 kilo: 10^3 mega: 10^8 giga: 10^9

SI prefixes: nano, micro, milli, centi, deci, kilo, mega, giga

average velocity

The change in position, divided by the time during which the change occurred; is the slope of an object's position-time graph

time interval

The difference between two times

dependent variable

The factor in an experiment that depends on the independent variable, the outcome factor; variable being measured

origin

The point at which both variables in a coordinate system have the value zero

The slope of a position vs time graph represents average velocity (average distance/time), The y intercept represents the object's starting position

Understand the significance of the slope and y-intercept of a line on a position vs. time graph

Accuracy descibes the nearness of a measurement to the standard or true value Example: in target shooting a high score indicates the nearness to the bull's eye and is a measure of the shooter's accuracy. Precision is the degree to which several measurements provide answers very close to each other, Precision is how close the measured values are to each other

What is the difference between accuracy and precision

magnitude

a measure of size

A motion diagram is a series of images showing the positions of a moving object taken at regular time intervals, a particle diagram is a simplified version of a motion diagram in which the moving object is replaced by a series of single points

explain the difference between a motion diagram and a particle model

Displacement is the distance from the starting point to wherever you stopped (final position - initial position). distance is how much you traveled to get there from the origin, Distance is the total length of the actual path between two points.Displacement is the length and direction of a straight line between starting and ending points

explain the difference between displacement and distance

A scalar quantity (speed, time, mass, distance) is a quantity with magnitude only. A vector is a quantity with both direction and magnitude, like velocity, displacement, acceleration, or force.

explain the difference between vector and scalar quantities in physics