Chapter 1 Motion
There are 1,000 meters in a
kilometer
The steepness of a line on a graph is called the
slope
To describe an object's motion, you need to know both its speed and its ________________________.
direction
An airplane is flying west at 200 km/h. Two hours later, it is flying west at 300 km/h. Its average acceleration is 100 km/h2.
false
Average speed is the rate at which an object is moving at a given instant.
false
If a toy car traveling at 10 cm/s passes a toy car moving at 10 cm/s in the opposite direction, both cars have the same velocity.
false
On a distance-versus-time graph, a straight line indicates that an object's speed is zero.
false
An object is _______________ if its position changes relative to another object.
in motion
A Ferris wheel turning at a constant speed of 5 m/s is not accelerating.
false
A speed-versus-time graph for a car's motion is a horizontal line at a speed of 12 m/s. The car's acceleration during this time is 12 m/s2.
false
An SI unit of velocity is the meter per second per second.
false
The SI unit for speed is m/min.
false
The slope of a line is found by multiplying the rise by the run.
false
A speedometer shows the ___________________ speed of a vehicle.
instantaneous
An airplane is accelerating at -8 m/s2. The distance the airplane travels each second is ________________ the distance it traveled during the previous second.
less than
If a car is speeding up, its initial speed is _________ than its final speed.
lower
Which of the following is the SI unit of acceleration?
m/s2
The SI unit for measuring distance is the_____________.
meter
The basic SI unit of length is the__________
meter
There are 1,000 __________ in a meter.
millimeters
On a graph showing distance versus time, a horizontal line represents an object that is
not moving at all.
A _______________ is a place or object used for comparison to determine if something is in motion.
reference point
If two lines appear on the same motion graph, the line with the steeper ______________ indicates a greater speed.
slope
Suppose you are sitting in a car at a red light when a car moving toward the north begins to pass you. If you use the passing car as a reference point, the direction in which you appear to be moving is toward the _____________________
south
Which of the following is the best reference point for describing the motion of the planets in our solar system?
the Sun
Jane is sitting in the family car. Her mother is driving her from their house to the library. Jane waves as she passes her friend Marina. Which of the following is not moving with respect to Jane?
the family car
Jeff is in a stationary school bus. Which is the best reference point for him to use to determine when the bus starts to move?
the front entrance of the school
Motion is measured relative to a reference point.
true
Speed in a given direction is called velocity.
true
To find the acceleration of an object moving in a straight line, you must calculate the change in distance for each unit of time.
true
When you know both the speed and direction of an object's motion, you know the
velocity of the object.
instantaneous speed
the speed of an object at one instant of time
A straight diagonal line on a distance-versus-time graph indicates constant speed.
true
If a train is slowing down, it is accelerating.
true
An amusement park ride falls straight down for 4 seconds. During this time, the ride accelerates from a speed of 0 m/s to 40 m/s. The ride's rate of acceleration during the 4 seconds is ___ m/s2.
10
How far did Kathy jog in the first 4 minutes?
600 m
Refrence point
A place or object used for comparison to determine if an object is in motion
Speed equals distance divided by
time
average speed
total distance divided by total time
A distance-versus-time graph will never show a horizontal line.
true
Alfonso ran the 1,000-meter race in 2.5 minutes. Alfonso's average speed was _________________ m/min.
400
An airplane is accelerating at 8 m/s2. Each second its speed increases by ______________ m/s.
8
International System of Units
A system of measurement based on multiples of ten and on established measures of mass, length, and time.
The International System of Units is used by scientists
all over the world.
The __________________ speed of an object is found by dividing the total distance by the total time.
average
If you know a car traveled 300 kilometers in 3 hours, you can find its
average speed
distance
The length of a path between two points
What happened to the speed of the ball during the final two seconds?
The speed increased by 2 seconds.
slope
The steepness of a line on a graph
On a distance-versus-time graph, a speed of zero would appear as a horizontal line.
True
A roller coaster is moving at 10 m/s at the top of a hill and 22 m/s at the bottom of the hill two seconds later. Explain how to find the average acceleration of the roller coaster, and then find the average acceleration.
What you do is you divide the total distance traveled by the total time. The average acceleration is 2.2.
Explain how to find the average speed of a car that travels 300 kilometers in 6 hours. Then find the average speed.
What you do is you find the average speed by the total time and you will get 50.
Which of these is an example of deceleration?
a car approaching a red light
A golf ball _______________ when either its speed or direction changes.
accelerates
An object changing direction is an example of
acceleration
The rate at which the velocity of an object changes is the object's rate of ______________________
acceleration
The rate at which velocity changes is called
acceleration
Speed
The distance an object travels per unit of time
Acceleration
The rate at which velocity changes
Motion
An object's change in position relative to a reference point.
Wind-up toy car A starts moving in one direction. After 1 unit of time, wind-up toy car B starts moving in the same direction and car A has traveled 5 cm. If, on a distance-versus-time graph, the two straight lines that represent their motions cross, which wind-up toy car is traveling faster? Explain.
Car A is moving faster because it is 1 cm faster that car B.
Car A is traveling north at 30 m/s and car B is traveling south at 30 m/s. If both cars have a southward acceleration of 1 m/s2, compare their speeds after 1 second. Explain your comparison.
Car A may be going slower that car b because it have a speed that is going to the south 1 m/s and in a minute it will be going 29 m/s.
_____________________ is the length of the path between two points.
Distance
The SI units for acceleration are km/h2.
False (m/s2)
Which is the best reason for not using a moving car as a reference point?
It is difficult to determine which direction motion is occurring
You are in a speedboat on a river moving in the same direction as the current. The speedometer on the boat shows that its speed is 20 km/h. However, a person on the shore measures the boat's speed as 23 km/h. How is this possible?
It is possible because the river is going 3 mph and that makes the boat go 3 miles faster
What two variables are plotted in the graph?
Kathy and Rachel
Does the graph indicate that the ball decelerated? Explain your answer.
No, because decelerating means it going down not staying the same.
Velocity
Speed in a given direction
What is the acceleration of the ball between 0 and 3 seconds?
The acceleration of the ball between 0 and 3 is 1 m/s.
