Exam 1

Question 1

Precision vs Accuracy

Answer 1

Precision- Getting the same answer over and over
Accuracy- Getting close to the right answer

Question 2

km
m
cm
mm

Answer 2

Question 3

What are the units for common physics problems
Distance
Velocity
time
acceleration

Answer 3

Distance- length is meter
Velocity- meter/ second
time- second
acceleration- m/s^2

Question 4

What is the rule of thumb about units/dimensions?

Answer 4

need to be dimensionally consistent. i.e units on the left of the equal sign must match the left over units on the right side. (Units must cancel to be equal)

Question 5

Unit conversions giga-pico

Answer 5

Question 6

Distance

Answer 6

Total length traveled. Always positive. most often need to convert to Meters

Question 7

Displacement

Answer 7

Change in position. Can be positive or negative to give direction

Question 8

Average speed

Answer 8

avg speed=distance/elapsed time

Always positive as distance and time are always positive.
SI units are meters/second, or m/s

Question 9

Average velocity

Answer 9

v.avg=displacement/time
change in x/change in t

where displacement is x.f - x.i
not always positive since displacement is directional
SI units are meters/second, or m/s

Question 10

Slope is equal to _______________

Answer 10

Slope is equal to the average velocity
therefore a negative slope means a negative velocity, moving backwards or to the left
change in x/change in t

Question 11

Instantaneous Velocity

Answer 11

This idea of a velocity corresponding to an instant of time

Question 12

When the velocity is constant, the ________ velocity over any time interval is
equal to the __________ velocity at any time.

Answer 12

When the velocity is constant, the average velocity over any time interval is
equal to the instantaneous velocity at any time.

Question 13

The instantaneous velocity at a given time is equal to the _______ of the ____________ at that point on an x-versus-t graph.

Answer 13

The instantaneous velocity at a given time is equal to the slope of the tangent line at that point on an x-versus-t graph.

Question 14

Acceleration
Average Acceleration

Answer 14

Rate of change of velocity with time.
Meters per second per second m/s/s

Question 15

equation for average velocity

Answer 15

Vavg= displacement/time

V= (Xf-Xi)/(Tf-Ti)

Question 16

equation for average speed

Answer 16

= distance/time

Question 17

When is instantaneous velocity equal to average velocity?

Answer 17

When the graph is a linear line. x vs t is linear progression

Question 18

An elevator is moving downward when the emergency button is pressed and comes to a stop a short time later.

After the button has been pressed but before it stops, the velocity of the elevator is _________ and the acceleration is ________

Answer 18

After the button has been pressed but before it stops, the velocity of the elevator is negative and the acceleration is positive

Question 19

A child throws a ball upward.

Immediately after the ball leaves the child’s hand, the velocity of the ball is ________ and the acceleration of the ball is _________

At the very top of the balls motion (maximum height) the velocity is _______ and the acceleration is ________

Answer 19

Immediately after the ball leaves the child’s hand, the velocity of the ball is positive and the acceleration of the ball is Negative

At the very top of the balls motion (maximum height) the velocity is zero and the acceleration is negative

Question 20

What is a vector

Answer 20

A vector is a mathematical quantity with both a magnitude and a direction

Question 21

What is a scalar

Answer 21

A scalar is a number with units. It can be positive, negative, or zero

Question 22

What is meant by magnitude?

Answer 22

Distance covered

Question 23

What is the slope equal to on an x vs t graph?

Answer 23

velocity- change in x / change in t

Question 24

What is the slope equal to on a v vs t graph?

Answer 24

acceleration- change in v / change in t

Question 25

What information can you gain from a v vs t graph?

Answer 25

The slope is equal to acceleration (V/t)

The area under the curve is equal to displacement.

Question 26

Acceleration v time graph

Answer 26

Question 27

Magnitude of a Vector

Answer 27

Question 28

Find the x and y component of a vector

Answer 28

x comp= Mag cos( degree)
y comp= mag sin (degree)

Question 29

Find the direction angle of a Vector

Answer 29

tan-1(y comp/x comp)