Science Chapter One- Reviews and Vocabulary

If you walk 2 km from your house to the store and then back home, what is your displacement?

0 km

To describe a position in more than one dimension you must use more than one- A. Displacement B. Reference direction C. Reference point D. Type of motion

B. Reference direction

An airplane rolls down the runway. For an airplane in motion, a reference point could be A. The cargo the plane carries B. The control tower C. The pilot flying the plane D. The plane swing

B. The control tower

Which describes the greatest displacement? A. Walking 3 m east, then 3 m north, then 3 m west B. Walking 3 m east, than 3 m south, then 3 m east C. Walking 3 m north, then 3 m south, then 3 m north D. Walking 3 m north, then 3 m west, then 3 m south

B. Walking 3 m east, then 3 m south, then 3 m east

Which is a unit of speed? A. h/mi B. km/h C. m^2/ s D. N*m^2

B. km/h

Which have the same velocity? A. A boy walking east at 2 km/h and a man walking east at 4 km/h B. A car standing still and a truck driving in a circle at 4 km/h C. A dog walking west at 3 km/h and a cat walking west at 3 km/h

C. A dog walking west at 3 km/h and a cat walking west at 3 km/h

If a model train moves 18.3 meters in 122 seconds, what is its average speed??

.15 m/s

If a car travels 45 km in one hour, then in each of the next 2 hrs it travels 78 km, what is its average speed??

67 km/h

Define reference point

A reference point is the starting point you choose to describe the location or position of an object

How can a roller coaster accelerate even when it has constant speed?

A roller coaster can accelerate when it changes direction, even when it is moving at a constant speed.

Define a speed-time graph

A speed time graph shows the relationship between speed and time and can be used to determine information about the acceleration of an object.

Which describes motion in two dimensions? A. A car driving through the city B. a rock dropping off a cliff C. A sprinter on a 100 m track D. A train on a straight track

A. A car driving through the city

Aaron leaves one city at noon. He has to be at another city 186 kilometers away at 3 PM the speed limit the entire way is 65 km/h. Can Aaron arrive at the second city on time? Explain.

Aaron is three hours to travel 186 kilometers at the rate of 16 km/h. Aaron will make it because if he went past the city he could travel 195 km in three hours. He could make it in three hours if his constant speed was 62 km/h, which is lower than the speed limit. So, yes he can make it.

Define acceleration

Acceleration is a change in velocity over time. An object accelerates when it speeds up, slows down, or changes direction.

Define acceleration in your own words.

Acceleration is the measure of change of speed and direction/velocity during a certain period of time. This includes speeding up, slowing down, or changing direction.

Define constant speed

An object moving the same distance each second is moving at a constant speed.

Define displacement

An object's displacement is the difference between its initial position and its final position

Define position

An objects position is it's distance and direction from a reference point

If the speed of a car on a straight track increases from 63 m/s to 75 m/s in 4.2 seconds, what is its acceleration??

Approx. 2.9 m/s^2

Write the 4 steps for making a distance time graph

Choose increments, label x and y axis, graph info, plot and connect dots

Define constant speed in your own words.

Constant speed is the rate of change of position in which the same distance is traveled each second. The speed is steady, and it does not change. The rate stays the same.

Which has the greatest average speed? A. A boat sailing 80 km in two hours B. A car driving 90 km in 3 hrs C. A train traveling 120 km in 3 hrs D. A bus traveling 50 km in 1 hour

D. A bus traveling 50 km in 1 hr

Which describes motion in which a person or object is accelerating? A. A bird flies straight from the tree to the ground without changing speed B. A dog walks at a constant speed along a straight sidewalk C. A girl runs along a straight path the same distance each second D. A truck moves around a curve without changing speed

D. A truck moves around a curve about changing speed

Which is a unit of acceleration? A. kg/m B. kg*m/s^2 C. m/s D. m/s^2

D. m/s^2

The difference between the initial position and the final positions of an object is its____________________.

Displacement

3 things for position

Distance, direction, reference point

Use acceleration in a sentence.

Example- While driving her car, my mother used acceleration when she slowed down at the stop sign.

After 2.0 seconds, Isabella was riding her bicycle at 3.0 m/s on a straight path. After 5.0 seconds, she was moving at a rate of 5.4 m/s. What is her acceleration?

Her acceleration is .8 m/s^2 because the formula for acceleration is: A= final speed-initial speed/ total time

After three seconds, Daniel was running at 1.2 m/s on a straight path. After seven seconds, he was running at 2.0 m/s. what was his acceleration?

His acceleration is .2 m/s^2 because of the acceleration formula: A= Final speed - initial speed/total time

Calculate - a truck driver travels 55 km in one hour. He then drives a speed of 35 km/h for two hours. Next, he drives 175 km in three hours. What was his average speed?

His average speed is 50 km/h because of the average speed formula. V=d/t 300/6 equals 50 km/h.

How can the position of an object be described in two dimensions?

It can be described by choosing a reference point and 2 reference directions, and then stating the distance along each reference direction.

A speed-time's graph has a line that is horizontal with a y-value of four. What is it indicating??

It is indicating that it has constant speed.

Describe - a ruler is on the table with the higher numbers to the right. An ant crawls along the ruler from 6 cm to 2 cm in two seconds. Describe the ant's distance, displacement, speed, and velocity.

Its distance is 4 cm. Its displacement is 4 cm. Its speed is 2 cm/s. It's velocity is 2 cm/s walking left.

Define motion in your own words.

Motion is the process of changing position

define motion

Motion is the process of changing position. Motion can be described with position, velocity, and acceleration.

Define speed

Speed is the distance an object moves per unit of time.

Distinguish between speed and velocity

Speed is the distance something traveled divided by the time elapsed. Velocity is speed and direction.

How can a bicyclist change the velocity in three ways?

Speed up, slow down, or change direction

Name the 4 types of speed time graphs

Speeding up, slowing down, object at rest, constant speed

Recall - how can you calculate average speed from a distance-time graph?

The average speed formula is distance divided by time equals average speed

A train traveled 350 km in 2.5 hours. What is the train's average speed?

The train's average speed is 140 km/h because of the average speed equation - V=d/t

Explain why a description of position depends on a reference point.

The description of position depends on a reference point because if your reference point is different than your friend's, your positions be different.

A race car accelerates on a straight track from 0 to 100 km/h in six seconds. Another race car accelerates from 0 to 100 km/h in five seconds. Compare the velocities and acceleration of the cars during the races.

The race car that accelerated in five seconds is faster than the car that accelerated in six seconds. It is this because of the same rate (speed) that they were going. The car that accelerated in five seconds has a higher final velocity and acceleration than the one that accelerated in six seconds.

Define instantaneous speed

The speed of an object at a certain moment is its instantaneous speed.

If your friend says that he is 30 m from the fountain in the middle of the city, why can you not know his exact position from this description?

This is because he did not describe his position in two dimensions. Yes, we know he is 30 m from the fountain, but where?? He needs to tell me the distances of each reference direction to the reference point. He already told us one of the reference's direction distance.

Define velocity and how it can change

Velocity is speed and direction. It can change when speed, direction, or both speed and direction change.

Define average speed and how to calculate it

You can calculate an objects average speed from a distance time graph by dividing the distance that object travels by the total time it takes to travel that distance. Average speed is the total distance traveled divided by the total time taken to travel that distance.

Relative to some reference points, your nose is in motion you run. Relative to others, it is not in motion. Give one example of each.

Your nose is in motion when the reference point is a tree. Your nose is not in motion when the reference point is your eyes.