Module 1 - quarterly test 1

Question 1

What’s the main difference between a scalar quantity and a vector quantity?

Answer 1

a vector quantity has information about direction, while a scalar quantity doesn’t

Question 2

On a physics test, the first question asks the students to calculate the acceleration of an object under certain conditions. Two students answer this question with the same number, but the first student’s answer is positive, while the second student’s answer is negative. The teacher says that they both got the problem 100% correct. How is this possible?

Answer 2

they defined their directions in the opposite way

Question 3

Which is a vector quantity: speed or velocity?

Answer 3

velocity

Question 4

What is the main difference between instantaneous and average velocity?

Answer 4

average velocity is measured over a finite time interval. Instantaneous velocity uses an infinitesimally small time interval.

Question 5

What physical quantity is represented by the slope of a position-versus-time graph?

Answer 5

velocity

Question 6

What do physicists mean when they say that velocity is relative?

Answer 6

the velocity an observer sees actually depends on the velocity of that ovserver

Question 7

You are reading through someone else’s laboratory notebook, and you notice a number written down: 12.3 m/sec2. Even though it is not labeled, you should immediately be able to tell what physical quantity the experimenter measured. What is it?

Answer 7

acceleration

Question 8

Another experiment in the same laboratory notebook says that an object has a 1.4 m/sec2 acceleration when it has a -12.6 m/sec velocity. At that instant in time, is the object speeding up or slowing down?

Answer 8

since velocity and acceleration have opposite signs, the acceleration is opposing the velocity. Thus, the object is slowing down.

Question 9

What kinds of graphs do you study if you are interested in learning about acceleration?

Answer 9

velocity-versus-time graphs

Question 10

An object’s velocity is zero. Does this mean its acceleration is zero? Why or why not?

Answer 10

No. Acceleration is the change in velocity. If the velocity is zero for a moment, then not zero the next moment, the velocity has changed, and therefore the acceleration cannot be zero.

Question 11

What is displacement?

Answer 11

The change in an object’s position

Question 12

What is vector quantity?

Answer 12

A physical measurement that contains directional information

Question 13

What is a scalar quantity?

Answer 13

A physical measurement that does not contain directional information

Question 14

What is velocity?

Answer 14

The time rate of change of an object’s position

Question 15

What is speed?

Answer 15

the time rate of change of the distance traveled by an object

Question 16

What is instantaneous velocity?

Answer 16

The velocity of an object at one moment in time

Question 17

What is average velocity?

Answer 17

The velocity of an object over an extended period of time

Question 18

How do you find the slope of a position-versus-time graph?

Answer 18

rise/run = final position - initial position/ final time - initial time

Question 19

What does the slope of a position-versus-time graph tell you?

Answer 19

The velocity. Position/time is like displacement/change in time = velocity

Question 20

What is acceleration?

Answer 20

The time rate change of an object’s velocity

Question 21

What does the slope of a velocity-versus-time curve tell you?

Answer 21

The acceleration. Velocity/time is like change in velocity/change in time = acceleration.

Question 22

If velocity is 0 does that mean acceleration is 0?

Answer 22

no. Because velocity can be 0 one moment, and not zero the next

Question 23

If acceleration is 0 does that mean velocity is 0?

Answer 23

No. Velocity can be a constant non-zero number