MT2: Motion and Stability Section2: Accelerated Motion
The equation for final velocity also can be used to calculate the initial velocity of an object when both the velocity and the time at which it occurred are given.
initial velocity
The _______________ of an object can be found by drawing a tangent line on the velocity-time graph at the point of time in which you are interested. The slope of this line is equal to the instantaneous acceleration.
instantaneous acceleration
The change in velocity at an instant of time is called ________________.
instantaneous acceleration
The change in velocity of an object at an instant of time is its ____ .
instantaneous acceleration
The slope of a tangent line on a velocity-time graph is the ____ .
instantaneous acceleration
The slope of the tangent line is equal to the _____________.
instantaneous acceleration
The graph shows that the car's motion is not uniform: Because The displacements for equal time intervals on the graph get_____________.
larger and larger
Acceleration is measured in _______
m/s^2
If a tossed ball had no velocity or acceleration, it would have ______________________.
no motion at all
A unique position-time graph cannot be created using a velocity-time graph because it does not contain any information about the _____________.
object's position
How do objects in free fall move?
only gravity
For an object with constant acceleration, the position-time graph is a _________.
parabola
You can determine the acceleration from a velocity-time graph by calculating the ________.
slope
When acceleration and velocity vectors are pointing in opposite directions, the object is ____ .
slowing down
You can determine the length and direction of an acceleration vector by.....
subtracting two consecutive velocity vectors and dividing by the time interval
You can determine the length and direction of an acceleration vector by __________ two consecutive velocity vectors and ________ by the time interval
subtracting----dividing
When the acceleration of an object is in the opposite direction, _______________________.
the object's speed decreases
When the acceleration of an object is in the same direction as its velocity, ________________.
the object's speed increases
What is acceleration?
the rate of change of velocity per unit of time.
Galileo concluded that objects in free fall have _________ accelerations.
the same
Often, it is useful to relate position, velocity, and constant acceleration without including ________.
time
Like displacement and velocity, acceleration is a ________.
vector
If an object's average acceleration during a time interval is known, then it can be used to determine how much the _____ changed during that time.
velocity
The slope of a tangent line on a displacement-time graph is equal to the object's ____ .
velocity
You need to know the direction of both the________________ in order to determine whether an object is speeding up or slowing down.
velocity and acceleration vectors
A ____ shows how velocity is related to time.
velocity time graph
Rearrange the _____________________________ to solve for tf = (vf − vi)/a.
velocity with average equation
The slopes from the position time graph can be used to create a _______________.
velocity-time graph
In a velocity-time graph velocity is plotted on the _______ axis and time is plotted on the __________ axis.
vertical----horizontal
If you toss a ball up, it reaches its maximum height when its velocity is ______.
zero
If you toss a ball up, its acceleration at its maximum height is ________.
-9.8 m/s^2 (opposite free-fall)
If a runner accelerates from 2 m/s to 3 m/s in 4 s, her average acceleration is ____ .
0.25 m/s2
If you drop a rock, its speed after 3 s will be _________.
29.9 m/s
What is free-fall acceleration?
9.8 m/s^2, downward (on Earth)
In cases in which the acceleration is _______________, the average acceleration (ā) is the same as the instantaneous acceleration (a).
constant
When the velocity of an object changes at a constant rate, it has a ______________.
constant acceleration
The decision to treat free-fall acceleration as positive or negative depends on the ___________ you use.
coordinate system
Free-fall acceleration is the same for objects of ________ sizes.
different
The area under a velocity-time graph is equal to the object's ____ .
displacement
Free-fall acceleration is always __________.
downward
The equation for ____________ can be rewritten to find the time at which an object with constant acceleration has a given velocity.
final velocity
The motion of falling objects when air resistance is negligible is called ____ .
free-fall
The acceleration of an object due only to the effect of gravity is known as ____________.
free-fall acceleration
The acceleration of an object in free fall that results from theinfluence of Earth's gravity is ____ .
free-fall acceleration
Free-fall acceleration is represented by the symbol _______.
g
Free-fall acceleration is represented by the symbol g. Near Earth's. surface, _________ downward.
g = 9.80 m/s^2
Acceleration can occur when speed is constant, but the direction of the object is _________.
changing
________ is the motion of a falling object when the air resistance is negligible.
Free fall
________ is the motion of an object when gravity is the only significant force acting on it.
Free fall
What do a position-time graph and a velocity-time graph look like for motion with constant acceleration?
If an object is moving with constant acceleration, its position-time graph is a parabola, and its velocity-time graph is a straight line.
What are the relationships among position, velocity, acceleration, and time
In motion with constant acceleration, position, velocity, acceleration, and time are related
Object D crosses the axis while maintaining a constant positive acceleration. What does this indicate?
It means it slows to a complete stop then stats again.
What information can you learn from velocity-time graphs?
It reveals useful information about the acceleration of the object.
How can you determine the displacement of a moving object from its velocity-time graph?
The area under an object's velocity-time graph is its displacement.
How is acceleration different from velocity?
Velocity is the rate of change of position with respect to time, whereas acceleration is the rate of change of velocity. Both are vector quantities (and so also have a specified direction), but the units of velocity are meters per second while the units of acceleration are meters per second squared.
The rate at which an object's velocity changes is its ____ .
acceleration
The slope on a velocity-time graph is equal to _____________
acceleration
a
acceleration
The rate at which an object's velocity changes is called the _______________ of the object.
acceleration (a)
A feather does not fall in the same way as a pebble because of __________.
air resistance
The ____ of an object is the change in velocity during some measurable time interval divided by that time interval.
average acceleration
The _____________ of an object is the change in velocity during some measurable time interval divided by that time interval.
average acceleration
