Science B1 Flashcards
What is motion
Motion is associated with many forms of energy. Motion is often described as Uniform or Non-uniform. Motion is the action of changing location or position. Motion can be expressed graphically or with the use of equations.
Uniform motion
travel at a constant velocity; with the same speed and direction. Uniform motion is often expressed as average speed. The mathematical expression of this is:
average speed = distance traveled
time elapsed
OR vavg = Δd = dfinal – initial
Δt tfinal – tinital
Significant Digits/Figures & Rounding (read)
When adding or subtracting, round the answer to the least number of decimal places: 1.457 + 83.2 = 84.657 -> 84.7
When multiplying or dividing, round the answer to the least number of significant digits: 4.36 x 0.00013 = 0.0005668 = 0.00057
Everything before the zero does not count as a sd, but everything after the # does.
Scientific Notation (read)
Scientific notation is a type of exponential notation used to express large or small numbers, or to round to the correct number of significant digits.
Examples include: 6.37 x 106 and 1.3 x 10-5
When the exponent is a positive number (like 6), this means that the decimal must be moved that many places to the right to convert the number to standard notation (6370000)
When the exponent is a negative number (like -5), this means that the decimal must be moved to the left that many places to convert the number to standard notation (0.000013)
0.00059 = 5.9 x 10^-4
Calculating the speed/velocity (m/s, km/h)
V=d (distance, i.e. km or m)
t (time, i.e. (s) (min) (h)
Calculating the distance
d= vt
Calculating the time
t= d
v
Graphing uniform motion (How will it be represented, what does the slope look like, axis)
On a distance–time graph, uniform motion will be represented by a straight line; having a constant slope.
Time will always be on the x axis, distance will be on the y. The slope of the line represents velocity. If the slope is flat on this graph, that means the object has stopped.
The Slope (what does it represent, formula, run, describe the slope)
The slope of the line represents the speed of the object.
Slope = Rise/Run, y2 - y1 / x2 - x1. the dot closest to the left represents x1 and y1. The run will never be negative. Run is located on the x axis.
The steeper the slope the greater the speed.
A slope that rises to the right indicates a speed in a
positive direction. A horizontal line reflects a slope of
zero and thus a speed of zero. A negative slope (falling
to the right) indicates that the speed is in a negative
direction.
Speed (velocity, m/s) vs time graph for uniform motion (how can it be illustrated, area, slope represents)
Uniform motion may also be illustrated by a flat line on a speed – time graph, which illustrates that the speed is
constant as time passes. The area represents distance.
The area under the line of a speed – time graph is equal to the distance travelled because area = altitude x base and d = vt (like a rectangle). The slope here represents acceleration. If the slope is flat, that means the object is moving at a constant velocity.
Scalar quantities
Quantities (such as distance and speed) which consist of
only a number (magnitude) followed by a unit, are called
scalar quantities.
Vector quantities
Quantities (such as displacement or position, velocity, and acceleration) that have direction as well as magnitude, are referred to as vector quantities. Vectors have an arrow written over the symbol to denote that direction is required:
-> ->
v = d
t
Vector Direction Sign Conventions
When performing 1D (linear) calculations:
north, east, up and to the right are considered to be +
south, west, down and to the left are considered to be -
Distance (what quantity is it, measurement)
Distance is a scalar quantity. It is a measurement of the change in distance of an object moving from a starting reference point.
Example:
In the diagram below, the person first moves 3 m to the right of the bus stop. Then he turns and moves 5 m back past the bus stop. The total distance traveled from the bus stop is: Δd = 3 m + 5 m = 8 m
Displacement (what quantity is it, measurement)
Displacement is a vector quantity. It is a measurement of the change in distance and the direction or the change in position of an object from a reference point. (total of the net distance travelled)
Example:
The diagram above shows the displacement of the person from his original starting point at the stop sign. The displacement from the starting point at the bus stop is: Δd = 3 m [right] + −5 m [left] = −2 m or 2 m left
Going to the left is negative, going to the right is positive
