1.3 Velocity-time Graphs Flashcards
What is the formula for calculating the slope of a velocity-time graph?
slope = rise/run
Where rise is the change in velocity (Δv–>) and run is the change in time (Δt)
What is the slope of the velocity-time graph in the given scenario?
A horizontal line at 4 km/h.
0 km/h²
Indicates there is no change in the plane’s velocity
What does a slope of zero in a velocity-time graph indicate about the object’s motion?
The object’s velocity is constant
There is no acceleration
What are the units of the slope of a velocity-time graph?
km/h2
m/s2
These units are also units of acceleration
What is the standard unit for acceleration in physics?
metres per second squared (m/s²)
This unit represents distance divided by time squared
Fill in the blank: Acceleration values can be recognized by their units, which are always _______.
units for distance divided by time units squared
True or False: If an object is moving at a constant velocity, its acceleration is zero.
True
Constant velocity implies no change in speed or direction
What is acceleration?
A vector quantity representing the change in velocity (magnitude or direction) per unit time.
Acceleration occurs when an object’s velocity changes over a time interval.
What type of motion is described when an object’s speed or direction is changing?
Non-uniform motion.
Non-uniform motion indicates that the object is undergoing acceleration.
What does it mean if an object is starting from rest and reaches a constant velocity?
The object undergoes acceleration during the time interval.
This means the object’s velocity changes from zero to a final non-zero value.
What is the variable used to represent acceleration?
a–>
Acceleration is important in understanding the motion of objects.
True or False: Acceleration can only be positive.
False.
Acceleration can be positive (increasing velocity) or negative (decreasing velocity).
Fill in the blank: Acceleration is a _______ quantity.
vector
This means it has both magnitude and direction.
What does a drag racer illustrate in motion?
Acceleration from rest to a constant velocity.
The drag racer example demonstrates how velocity changes over time.
What does calculating the slope of a line or curve at a single point represent?
Finding an instantaneous value
What does calculating the slope between two points represent?
Finding an average value
Define tangent in the context of a curve.
A straight line that touches a curved-line graph at only one point
What is instantaneous velocity?
The moment-to-moment measure of an object’s velocity
How can you describe a trip using instantaneous velocities?
By recording the speed of your car once every second
What is required to determine the velocity of an object from a position-time graph?
Calculating the slope of the position-time graph
What does each point on a curve indicate?
The position of the object at an instant in time
How do physicists determine the velocity of an object at any instant?
By using tangents
What does each tangent on a curve represent?
The velocity at that instant
What must be true for an object to have an instantaneous velocity at a certain position and time?
It must have an instantaneous velocity equal to the slope of the tangent at that point
What do determining the slopes of the tangents at different points on a position-time curve provide?
The instantaneous velocities at different times
Fill in the blank: A tangent is a straight line that touches a curve at only one _______.
point
True or False: Instantaneous velocity can be derived from the average velocity.
False
Fill in the blank: To find the instantaneous velocity, physicists use _______.
tangents
What is the slope of a position-time graph?
Velocity
The slope indicates how position changes over time.
What do the slope values of position-time graphs represent?
Instantaneous velocities at given times
These values are used to create a velocity-time graph.
What type of graph is created using the slopes of position-time graphs?
Velocity-time graph
The graph indicates the change in velocity over time.
What does it mean if a velocity-time graph is a straight line that goes through the origin?
The dragster has started from rest (0 velocity)
This indicates the initial condition of the motion.
What does a positive slope on a velocity-time graph indicate?
The object is undergoing uniformly accelerated motion
This implies a constant acceleration.
What are the units of the slope of a velocity-time graph?
m/s²
These units represent acceleration.
What is uniformly accelerated motion?
Constant change in velocity per unit time
This describes motion where acceleration remains constant.
True or False: If the velocity-time graph has a non-zero slope, the acceleration is constant.
True
A straight line on the velocity-time graph indicates constant acceleration.
Fill in the blank: When jet fighters come in to land on an aircraft carrier, they stop so quickly that pilots sometimes lose _______.
Consciousness
This is due to the enormous acceleration experienced during landing.
What can happen to pilots when they eject from an aircraft?
They can lose consciousness due to enormous acceleration
This is similar to the experience during rapid deceleration in landings.
What does negative acceleration mean?
It indicates that the acceleration value is negative, but it does not necessarily mean the object is slowing down.
How should you interpret the sign of acceleration?
You need to compare it to the sign of velocity.
What happens when the directions of velocity and acceleration are the same?
The object is speeding up.
In the case of a drag racer speeding up, how are velocity and acceleration related?
The direction of its velocity is the same as the direction of its acceleration.
Fill in the blank: When the directions (signs) of velocity and acceleration are ______, the object is speeding up.
[the same]
True or False: Negative acceleration always means an object is slowing down.
False
