Chapter 9 Test: Motion

Front 1

When is an object in motion?

Back 1

When its distance from another object is changing.

Front 2

What is a reference point?

Back 2

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

Front 3

How can you determine if an object is in motion in relation to a reference point?

Back 3

An object is in motion if it changes position relative to a reference point

Front 4

Why is it important for the reference point to be stationary?

Back 4

A reference point should be stationary to determine if something else is moving or not

Front 5

Name some good reference points.

Back 5

Sidewalk, tree, concrete bench (objects that are motionless)

Front 6

Suppose you are riding in a train. Describe your motion relative to the train.

Back 6

In relation to the train you are not moving but are moving along with the train. Describe your motion relative to the buildings outside. The buildings are moving past you according to your frame of reference.

Front 7

Suppose you are riding in a train. Describe your motion relative to the sun.

Back 7

You would not notice any movement relative to the sun.

Front 8

Now suppose you walk to the back of the train while the train is in motion. Describe how an observer outside might see your motion, and how a passenger on the train would see your motion.

Back 8

An observer outside the train would see the passenger as moving toward him slightly since the train is moving forward. A passenger on the train would see you walking toward him, and then away as you pass him.

Front 9

Suppose you are on the train in a subway and you look out the window and see a train next to you. The other train begins to move but you feel as though your train is moving backwards. Explain what is happening.

Back 9

The train next to you is moving forward and since your train is not moving it gives the false feeling of backwards movement since you are using a moving object as a reference point.

Front 10

If you are riding on a bike traveling 15 km/h and a car approaches you traveling 30 km/h, relative to the bike, how fast is the car going?

Back 10

Relative to the bike, the car is going 45 km/h.

Front 11

10. How fast would the car be going relative to the bike if the car was traveling 30 km/h in the same direction as the bike traveling 15 km/h?

Back 11

15 km/h.

Front 12

If the car and bike were traveling side by side at 20 km/h, what would the bikes motion be relative to the car?

Back 12

The car and bike would have no motion relative to each other.

Front 13

What does SI stand for?

Back 13

International System of Units (System Internationale)

Front 14

What is the metric unit for distance?

Back 14

meter

Front 15

What unit is used for length, width, and height?

Back 15

meter

Front 16

What is a geocentric model of the solar system?

Back 16

The earth is the reference point, thought to be the center of the universe, everything revolved around the earth.

Front 17

What is a heliocentric model of the solar system?

Back 17

The sun is the reference point, the center of the universe.

Front 18

Write a sentence about a geocentric model of the solar system using the words "reference point".

Back 18

The earth was thought to be a good reference point because people saw everything moving around the earth especially since they could not feel the earth move.

Front 19

Write a sentence about a heliocentric model of the solar system using the words "reference point".

Back 19

When the sun is the reference point it is stationary and everything else revolves around it.

Front 20

How can you calculate the speed of an object in motion?

Back 20

Speed=distance/time

Front 21

What is average speed?

Back 21

It is the total distance divided by the total time.

Front 22

What is instantaneous speed?

Back 22

speed at a particular instant (there are no calculations involved).

Front 23

If an asteroid travels 4500km in 60 sec, what is its speed?

Back 23

4500km/60sec = 75km/sec

Front 24

If a cyclist travels 20 miles in 30 minutes, what is the cyclist’s average speed?

Back 24

20m/30min = .66mi/min

Front 25

If a cyclist looks at his odometer and it reads 20 km/h, he has read his ___________________ speed.

Back 25

instantaneous