Conceptual Physics-Laws of Motion Unit-Speed Quiz-Pages 4/11 and 13A

Question 1

motion

Answer 1

a change in position relative to a frame of reference

Question 2

What is the equation for average speed?

Answer 2

Velocity=total distance/total time

Question 3

What does the delta symbol stand for?

Answer 3

change in

Question 4

If you measure distance in meters and time in seconds, what units would be used for speed?

Answer 4

meters per second

m/s

Question 5

How is average speed different from constant speed?

Answer 5

Average speed means that the speed at any given time will be different from any other given time (but in the end these changes will average out), while a constant speed never changes.

Question 6

Give an example of when you would use average speed as opposed to constant speed.

Answer 6

A road trip

Races

Question 7

Give an example of when you would use constant speed as opposed to average speed.

Answer 7

treadmill
cruise control
clock

Question 8

What is a time interval? Use the example of a twenty meter race with five meter splits.

Answer 8

A time interval is the time it took to cover a certain part of a distance. For example, the time interval for the five to ten meter section of a twenty meter race would be the time from the start to the ten meter mark MINUS the time to the five meter mark. The change in time between the five and ten meter marks.

Question 9

How would you find the speed for a five meter split?

Answer 9

You would take the time interval for that section of the track, then divide five by that number. Meters divided by seconds.

Question 10

velocity

Answer 10

speed in a certain direction; the rate at which you change position

Question 11

Rearrange the velocity formula to find distance.

Answer 11

distance=velocity x time

Question 12

Rearrange the velocity formula to find time.

Answer 12

time=distance / velocity

Question 13

In a track that starts high, dips down, then returns to the starting height in some shape, when a marble is dropped from various points on the track and the recovery distance is measured, from what point will the recovery distance be greatest?

Answer 13

The lowest points

Question 14

Why would the recovery distance in the bowl shaped track be greatest from the point that it is?

Answer 14

The gravitational force is slightly stronger at the top of the track, so as the marble ascends, it becomes harder and harder for it to continue, so it is easier to go farther (take greater advantage of the force the marble gained rolling down the first slope) when the marble’s overall recovery area is lower on track.

Question 15

How far along a horizontal track that started with a downward slope would a marble need to roll to recover its starting height?

Answer 15

It could never recover its starting height.

Question 16

How far along a horizontal track that started with a downward slope would a marble roll?

Answer 16

It would roll for a very very long time unless it was stopped by an object in its path or some other force.

Question 17

In a plane traveling at speed, if someone got out of their seat and jumped straight up, where would they land?

Answer 17

They would land right next to their seat. When they jumped, they jumped with the combined force of their muscles and the plane’s movement, so that they jumped as far as the plane itself moved in addition to a little bit upwards.

Question 18

Why would a penny resting on a note card resting on a beaker fall into the beaker when the note card is pulled away, as opposed to moving with the note card?

Answer 18

The penny has a little inertia, and so wants to stay where it is. This force is greater than the friction with which the card pulls it along, so it is still over the beaker when the card is gone, and so falls into it with gravity.

Question 19

Acceleration

Answer 19

change in velocity; can include speeding up, falling down, changing direction, stopping, or starting

Question 20

force

Answer 20

a push or pull; can be visible, such as a physical push or pull, or invisible, such as the forces of gravity, magnetism, and friction

Question 21

Balanced Forces

Answer 21

equal and opposite; do not cause a change in motion, or cause any motion at all; balanced forces cause things in motion to stay in motion at a constant speed, in a straight line; net force is zero; Newton’s first law applies

Question 22

Vectors

Answer 22

arrows whose size and direction represent those of forces

Question 23

Net Force

Answer 23

sum of all the forces on the object

Question 24

Unbalanced forces

Answer 24

are either unequal or in the same direction; always cause a change in motion; Newton’s second law applies

Question 25

How do you determine the net force of unbalanced forces?

Answer 25

If in opposite directions, but unequal: subtract

If in the same direction: add

Question 26

If an object is thrown by someone riding in a wagon, at what speed is the object thrown?

Answer 26

The combined speed of the person’s arm and the wagon

Question 27

Inertia

Answer 27

natural tendency of an object to resist changes in its motion; direct relationship with mass

Question 28

Newton’s First Law

Answer 28

In the absence of an unbalanced force (or When forces are balanced), an object at rest will remain at rest, and an object in motion will remain in motion with constant speed in a straight line path.