1.1 Intro To Physics: Units, Accuracy, Uncertainty, Kinemarics Flashcards
Define the concept of a unit
A unit is a unique name we assign to measures (meter) of that quantity (length)
The Fundamental quantities of physics are
Length
Time
Mass
Electrical current
Temperature
Amount of substance and luminosity
What system of units is used in physics
The SI system which contains base units like metre for length, seconds for time and kg for mass.
Type of physical quantity: length
Unit?
Metre (m)
Type of physical quantity: time, duration
Unit?
Second (s)
Type of physical quantity: mass
Unit?
Kilogram (kg)
Type of physical quantity: current
Unit?
Ampere (A)
Type of physical quantity: thermodynamic temperature
Unit?
Kelvin (K)
Type of physical quantity: luminous intensity
Unit?
Candela (cd)
Type of physical quantity: amount of substance
Unit?
Mole (mol)
Nano (n)
10^-9
Micro (μ)
10^-6
Milli (m)
10^-3
Kilo (k)
10^3
Mega (M)
10^6
Giga (G)
10^9
Accuracy?
How close something is to the accepted standard. To closer the more accurate
Precision?
The consistency of something
Not necessarily related to the accepted standard.
3 rules for significant figures?
- Use all digits while solving. Solution can be rounded not the steps leading to the solution.
- When multiplying or dividing two numbers the solution should be rounded to the same number of significant figures as the number in the calculation with the least significant figures
- When adding or subtracting numbers the solution should be rounded to the same number of decimal places as the number in the calculation with the least number of decimal places
How many sig figs in 0.00682
3 the 6 8 and 2 because leading zeros are never significant
Scientific notation for 0.00682?
To the right (-) so 6.82 x 10^-3
Sig figs 1.072?
4, imbedded zeros in between numbers are always significant
Scientific notation 1.072?
1.072 (x 10^0)
Sig figs 300?
1, trailing zeros are only significant if there is a decimal point
Scientific notation 300?
3 x 10^2 (100) not 3.00, decimal only if original number had a decimal
Sig figs 300. ?
3, trailing zeros are only significant if there is a decimal point (which there is)
Scientific notation 300. ?
Left is (+), 3.00 x 10^2
Sig figs 300.0 ?
4, trailing zeros are only significant if there is a decimal point
Scientific notation 300.0 ?
3.000 x 10^2
Sig figs 1.0 and 1.10?
2 and 3, trailing zeros are only significant if there is a decimal point and the above are considered trailing zeros
What to do when confused with sig figs
Convert into Scientifiv Notation then count the number/s before the x10
What is the length of the path an object takes when travelling from point A to point B?
Distance
Distance is a ________ quantity
Scalar
Scalar means
Magnitude only
The distance travelled with direction associated is
Displacement
Displacement is a _______ quantity
Vector
Vector means
Magnitude and direction.
If an object moves from x1=5m to x2= 200m and back to x1= 5m, the displacement from start to finish is?
0, since its the overall change in position and there it is currently at the same position
If a question asked for direction and displacement with units of distance and direction we
Use the units for distance for distance (miles) and units of distance and direction for displacement (miles, East)
Average velocity is defined as
Displacement divided by the elapsed time
Average Velocity is represented with the unit
m/s
Since average velocity includes displacement and displacement is vector then velocity is
Vector (signifies both magnitude- of how fast movement is and direction)
_________ is how fast a particle/object is moving
Average speed
Speed is represented as
Distance over time
Since average speed involves the total distance (independent of direction- not including direction), speed is
Scalar
An object whose velocity is changing is said to be
Accelerating
When an objects velocity changes from 0 to 80 km/h it is
Accelerating (change in velocity)
Acceleration specifies how rapidly the velocity of an object is changing; therefore, average acceleration is defined as
Change in velocity over the change of time
What is m/s^2 a common unit of
Acceleration
All objects falling freely towards earth have the same acceleration of
9.81 m/s^2
The value of constant acceleration g=9.81 m/s^2 is more commonly known as
Acceleration due to gravity
What does the following graph represent
An object at rest
150
nm stands for nano meter and is 10^-6 true or false
False 10^-9
The Si unit of Speed (v) is
Meter per second, m/s
