chapter 11 physical science
Acceleration can be the result of a change in _______ at a constant speed. (for example: riding a bicycle around a curve)
direction
Sometimes knowing only the speed of an object isn't enough. You also need to know the ____ of the objects motion.
direction
To describe motion, you must state the ____ the object is moving as well as how _____ the object is moving. You must also tell its location at a certain time.
direction, fast
Length of a path between two points
distance
______ is the length of a path between two points. when an object moves in a straight line, the distance is the length of the line connecting the objects starting point and its ending point.
distance
How are distance and displacement different?
distance is the length of a path between two points. displacement is the direction from the starting point and the length of a straight line from the starting point to the ending point.
on a speed-time graph of a bicycle slowing to a stop, a line sloping _______ represents the bicycle decelerating
downward
To describe an objects position relative to a given point, you need to know how ___ away and in what _____ the object is from that point. displacement provides this information.
far, direction
A longer vector represents a _____ speed, and a shorter one a _____ speed.
faster, slower
How fast the passengers on a train are moving depends on the ____ ___ ______ chosen to measure their motion
frame of reference
System of objects that are not moving with respect to one another
frame of reference
Movement of an object toward earth solely because of gravity
free fall
Each second an object is in free fall, its velocity increases downward by 9.8 meters per second squared. The change in the objects speed is 9.8 m/s^2, the acceleration due to _____
gravity
A steeper slope on a distance-time graph indicates a _____ speed
higher
The vectors length depends on how fast what?
how fast velocity is changing
If you are coasting downhill on a bicycle, your velocity ______, and your acceleration is ________
increases, positive
An increasing slope on a distance time graph of accelerated motion means that the speed is _______
increasing
The acceleration at a specific point on a distance-time graph is the _________ ________.
instantaneous acceleration
What is instantaneous acceleration?
instantaneous acceleration is how fast a velocity is changing at a specific instant
Rate at which an object is moving at a given moment in time
instantaneous speed
_______ ___ is the rate at which an object is moving at a given moment in time
instantaneous speed
For very large distances, it is more common to make measurements in ________
kilometers
The SI unit for distance that would be most appropriate for measuring the distance between two cities is _______
kilometers
The magnitude can be size, ____, or ______
length, or amount
Displayed data forms straight line parts
linear graph
The SI unit for measuring distance is the _____
meter
What is the unit for velocity?
meters per second
What is the unit for acceleration?
meters per second squared
A distance-time graph is a good way to describe _____
motion
If the velocity decreases, the acceleration is ______.
negative
Mike pedals up a hill and gradually slows from 20m/h to 5km/h. This is an example of_______ acceleration
negative
A curve connects the data parts that are plotted
non linear graph
in a ________ ___, a curve connects the data points that are plotted
nonlinear graph
If the velocity increases, the acceleration is _____.
positive
Movement in relation to a frame of reference
relative motion
______ ____ is movement in relation to a frame of reference
relative motion
Vector sum of two or more vectors
resultant factor
____ is the change In the vertical axis value divided by the change in the horizontal axis value
slope
If the motion is in a straight line, velocity can be treated as _____, and acceleration is the change in speed divided by time.
speed
Ratio of distance an object moves to the amount an object moves
speed
______ is the ratio of the distance an object moves to the amount of time the object moves
speed
Sometimes motion is characterized by changes in both _____ and _____ at the same time
speed and direction
The _______ in a car measures the cars instantaneous speed.
speedometer
If two displacements are in opposite directions, the magnitudes ______ from each other
subtract
How do you determine a change in velocity?
subtract one velocity vector from another
A horse on the carousel is traveling at a constant speed, but is accelerating because why?
the direction is constantly changing
How can you find the speed from a distance-time graph?
the slope of a line on a distance-time graph is the speed
How do velocities add?
two or more velocities add by vector addition
Acceleration and Velocity are both ______ quantities.
vector
Quantity that has magnitude and direction
vector
In science, acceleration applies to any change in an object's ____
velocity
Sometimes the motion of an object involves more than one _____
velocity
Together, the speed and direction at which an object is moving
velocity
Together, the speed and direction in which an object are moving are called ______
velocity
How are speed and velocity different?
velocity is a description of both speed and direction of motion. velocity is a vector.
You can use a graph to calculate acceleration. Graph speed on the _______ axis and time on the _______ axis.
vertical, horizontal
For an object that is standing still, the acceleration vector is ____
zero
A car traveling at 10m/s starts to decelerate steadily. It comes to a complete stop in 20 seconds. What is its acceleration?
-0.5m/s^2
You travel 18km west of your home and then turn around and start going back home. After traveling 4km east, what is your displacement from your home?
14 km west
You travel 12km east of your home, stop at a red light and continue traveling 7 km east. What Is your final displacement from your home?
19 km east.
A child drops a ball from a bridge. The ball strikes the water under the bridge 2.0 seconds later. What is the velocity of the ball when it strikes the water?
20m/s
An airplane travels down a runway for 4.0 seconds with an acceleration of 9.0m/s^2. What is its change in velocity during this time?
36 m/s
A ball rolls down a ramp, starting from rest. After 2 seconds, its velocity is 6 meters per second. What is the Acceleration of the ball?
3m/s^2
A woman jogs 8 kilometers in one hour, stops at a park for one hour, and then walks 7 kilometers in two hours. What is her average speed for the outing?
5km/hour
A sports car can accelerate from 0m/s to 28m/s in four seconds. What is the acceleration of the car?
7m/s^2
You travel 35 kilometers in 0.4 hour, followed by 53 kilometers in 0.6 hour. What is your average speed?
88km/hour
Objects falling near Earth's surface accelerate downward at a rate of _____
9.8m/s^2
How are changes in velocity described?
The rate at which velocity changes is acceleration
How does a speed-time graph indicate acceleration?
The slope of a speed-time graph is the acceleration.
If you were to sketch a displacement-time graph for an object experiencing constant acceleration, what would they look like?
The speed-time graph would be linear; the displacement -time graph would be nonlinear
What is needed to describe motion completely?
a frame of reference is necessary
How do you add displacements?
a vector is a quantity that has magnitude and direction, add displacements using vector addition
A roller coaster produces ____________ due to changes in both speed and direction.
acceleration
Rate at which velocity changes
acceleration
The slope is the change in speed divided by change in time, which is equal to the _______
acceleration
What is the formula to find acceleration?
acceleration= final velocity - initial velocity / time
Acceleration involves a change in velocity or direction or both, so the vector of acceleration can point in __ ______
any direction
Two ways to express the speed of an object are ____ and ______ speed
average and instantaneous
Total distance traveled divided by total time spent
average speed
_______ ____ is the total distance traveled, d, divided by the time, t, it takes to travel that distance
average speed
How are instantaneous speed and average speed different?
average speed is computed for the entire duration of a trip, and instantaneous speed in measured at a particular instant
Distances that are smaller than a meter are measured in ______
centimeters
________acceleration is represented on a speed-time graph by a straight line.
constant
Steady change in velocity
constant acceleration
_______ ______ is a steady change in velocity
constant acceleration
The velocity of an object moving in a straight line changes at a ______ ____ when the object is experiencing ______ ______
constant rate, constant acceleration
Acceleration is rarely _____, and motion is rarely in a ______ ____
constant; straight line
accelerated motion is represented by a ____line on a distance-time graph
curved
_________ is an acceleration that slows an object's speed
deceleration
Constant negative acceleration _________ speed
decreases
If you continue coasting on level ground, your velocity ______, and your acceleration is _______.
decreases, negative
Acceleration can be caused by negative and positive changes in speed. Negative meaning _______, and positive meaning ______
decreasing, increasing
Name three vector quantities.
1. Displacement 2. Velocity 3. Acceleration
true or false: If an object experiences a steady velocity change in a straight line, it is undergoing constant acceleration.
True
How can you calculate acceleration?
You calculate acceleration for straight-line motion by dividing the change in velocity by the total time.