Motion

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 seconds is 1 m/s

What happened to the speed of the ball during the final two seconds?

The ball stopped accelerating during the final two seconds, so the graph shows the straight line so it could demonstrate that the ball has stopped accelerating after 3 seconds, and then traveled the same speed.

To describe an object's motion, you need to know both its speed and its________

direction? idk

A speedometer shows the________ speed of a vehicle.

directional? idk

What two variables are plotted in the graph?

distance/time

True or False? The SI unit for speed is m/min.

false (m. s.)

An object is_________if its position changes relative to another object.

in motion

There are 1,000 meters in a

kilometer

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________its final speed.

less than

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

The steepness of a line on a graph is called the

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

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

instantaneous speed

the speed of an object at one instant of time

Speed equals distance divided by_________

time

average speed

total distance divided by total time

When you know both the speed and direction of an object's motion, you know the

velocity of the object.

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

Alfonso ran the 1,000-meter race in 2.5 minutes. Alfonso's average speed was______m/min.

400

How far did Kathy jog in the first 4 minutes?

600 m

An airplane is accelerating at 8 m/s2. Each second its speed increases by____________m/s

8

Reference point

A place or object used for comparison to determine if an object is in motion

International System of Units

A system of measurement based on multiples of ten and on established measures of mass, length, and time.

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.

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.

Wind-up toy car B is moving faster because it started off later but caught up to A, so that means it ended up going faster than A.

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

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.

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.

After 1 second, the cars are traveling at the same speed because they are accelerating at the same speed because they were already at the same speed.

Motion

An object's change in position relative to a reference point.

________________is the length of the path between two points.

Distance

True or False? A Ferris wheel turning at a constant speed of 5 m/s is not accelerating.

False

True or False? A distance-versus-time graph will never show a horizontal line.

False

True or 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

True or False? An SI unit of velocity is the meter per second per second.

False

True or False? 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

True or False? Average speed is the rate at which an object is moving at a given instant.

False

True or 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

True or False? On a distance-versus-time graph, a straight line indicates that an object's speed is zero.

False

True or False? The SI units for acceleration are km/h2.

False

True or False? The slope of a line is found by multiplying the rise by the run.

False

True or False? To find the acceleration of an object moving in a straight line, you must calculate the change in distance for each unit of time.

False

speed

The distance an object travels per unit of time

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

Distance

The length of a path between two points

Acceleration

The rate at which velocity changes

slope

The steepness of a line on a graph

Does the graph indicate that the ball decelerated? Explain your answer.

This graph does not indicate that the ball decelerated because if the ball were to be decelerating, it would show that the line is moving downward, although, at the end of the graph, it is showing a straight line, which indicates that the ball is not accelerating or decelerating speed after 3 seconds. This is why the ball is not decelerating.

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?

This is possible because the boat is not accelerating on its own, yet the current is moving it, so, the current is the cause of the differences between these two speeding measures.

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.

To find the average acceleration you would have to take the change in speed or velocity divided by time. The change in speed is 12 m/s (22-10). And, if you divide that by time, (2 seconds), the acceleration is 12 divided by 2. So, the average acceleration is 6 m/s.

Explain how to find the average speed of a car that travels 300 kilometers in 6 hours. Then find the average speed.

To find the average speed of a car that travels 300 kilometers in 6 hours, you would have to divide the total distance traveled by the total time. Therefore, this problem would be 300 divided by 6. The average speed of a car that travels 300 kilometers in 6 hours is 50 km/h.

True or False? A straight diagonal line on a distance-versus-time graph indicates constant speed.

True

True or False? If a train is slowing down, it is accelerating.

True

True or False? Motion is measured relative to a reference point.

True

True or False? On a distance-versus-time graph, a speed of zero would appear as a horizontal line.

True

True or False? Speed in a given direction is called velocity.

True