Unit B Energy Flow in Technological Systems : Section 1.0 Flashcards
How can we tell if an object has moved?
We can analyze the motion of an object in comparison to another point
What is a reference point?
A point that we use to analyze the motion of an object
When does the motion of an object occur?
When an imaginary line attached to the reference point increases or decreases in distance or changes direction.
What is uniform motion?
When an object is traveling at constant rate of motion in a constant direction
What is average speed?
A uniform motion that involves traveling a distance in a specific time
What does the letter v mean in a mathematical formula?
Speed
What does a triangle mean before a letter in a chemical formula?
Difference in
What is the formula for average speed?
v = d/t
or (final position - initial position)/ change in time
What is the formula for slope?
Rise/run
Change in y / change in x
Change in dependent variable / change in independent variable
Where does time go on a distance-time graph?
On the x-axis
Where does distance go on a distance-time graph?
The y-axis
What does a slope calculate in a distance-time graph?
Average speed
What does a straight line in a distance-time graph represent?
Uniform motion (constant speed)
What does a straight horizontal line on a speed-time graph represent?
the speed remains constant
What does the slope of a speed-time graph confirm?
Whether or not the motion is uniform, because when the slope is 0, the speed is constant and thus you have uniform motion.
You can also know the acceleration specifically.
How can you calculate the distance an object traveled on a speed-time graph?
By calculating the area underneath the graph
What is velocity?
The rate of motion and direction of an object
What is a scalar quantity?
A scalar quantity only represents the magnitude or how much and does not include direction
What is a vector quality?
A vector quality includes the magnitude or how much and a direction
How can you tell if something is a vector quality?
It will include an arrow showing direction
What is distance?
A scalar quantity that measures the distance traveled by an object from a reference point
What is displacement?
a vector quantity is a change in distance and direction from a reference point
What is the formula for average velocity?
displacement / time elapsed or
final distance - initial distance / final time - initial time
What does the slope represent on a position-time graph?
Velocity
What goes on the x-axis on a position-time graph?
Time t (s)
What goes on the y-axis on a position-time graph?
Position d (m)
Is acceleration a vector or scalar quanitity?
Vector
What is acceleration?
Change in velocity in different specific time intervals
What are the 2 ways of positive acceleration?
- When an object has a positive magnitude of velocity and is increasing in a positive direction
- When the change in velocity is negative and the direction is negative
What are 2 ways of negative acceleration?
- When the direction is negative and the change is velocity is positive
- When the change in velocity is negative and the direction is positive
What is the formula for acceleration?
Acceleration = change in velocity/change in time
For acceleration, what will the best fit line look like on a position time graph?
A smooth curve
What will a positively accelerating slope look like?
Will start from zero and look like half of a happy face
What will a negatively accelerating slope look like?
Start at 0 and look like half of a sad face
What will you figure out if you calculate the slope of a velocity-time graph?
The acceleration
What is a force?
A push or pull on an object
What is force measured in?
Newtons (N)
What happens in an unbalanced force?
The force acting in one direction is greater than the force in the opposite direction and thus movement occurs
What is work?
When energy is applied to an object and it moves a distance
What is the formula for work?
Work = force x distance
What is work measured in?
Joules
Also (kg)(m/s²)(m) since force times distance is work. Use Joules when recording your final answer.
What is 1 joule equal to?
(1kg x m/s²) x m
Since force times distance is work and work is energy. Force is mass times acceleration. Here force is measured with kg times m/s². Distance is measured with metres.
also Nm Newton metre
What are the 3 conditions for work to be done on an object?
- Must be movement
- There must be a force
- The force and distance must be in the same direction
What should be equal to work output?
Work input if there is the absense of friction
