Physics Ch 2

Question 1

Kinematics

Answer 1

study of motion without considering its causes; Greek for motion

Question 2

One-dimensional motion

Answer 2

motion along a straight line

Question 3

Position

Answer 3

where an object is at any particular time; needs to be specified relative to a convenient reference frame

Question 4

Displacement

Answer 4

change in position of an object relative to a reference frame; delta x (x=change in position) = final position - initial position; unit = meter; has direction and magnitude; vector quantity

Question 5

Distance

Answer 5

magnitude or size of displacement between 2 positions; has no direction

Question 6

Distance Traveled

Answer 6

total length of the path traveled between 2 positions; scalar quantity

Question 7

Magnitude of displacement

Answer 7

displacement without regards to direction; same as distance

Question 8

Vector

Answer 8

any quantity with both magnitude and direction (ex. displacement, velocity, force); direction expressed with plus or minus; arrow used to represent a this has a length proportional to the magnitude

Question 9

Scalar

Answer 9

any quantity that has a magnitude but no direction (ex. temperature, calories, speed limit, height, distance); can be negative (expressing a point on a scale rather than a direction); never represented by arrows

Question 10

Time

Answer 10

change; the interval over which change occurs; calibrated by comparison with a standard; unit = second

Question 11

Elapsed time (delta t)

Answer 11

difference between the ending time and beginning time; delta t = final time - initial time

Question 12

Average velocity (v with a bar over it)

Answer 12

displacement (change in position) divided by the time of travel; bar v = delta x (displacement)/time; SI unit = m/s

Question 13

Instantaneous velocity (v)

Answer 13

average velocity at a specific instant in time (or over an infinitesimally small time interval)

Question 14

Instantaneous speed

Answer 14

magnitude of instantaneous velocity

Question 15

Average speed

Answer 15

distance traveled divided by elapsed time

Question 16

Acceleration

Answer 16

the greater this is, the greater the change in velocity over a given time; = a vector in the same direction as the change in velocity; a change in speed or direction, or both; in the same direction as its motion

Question 17

Average Acceleration (a with a bar over it)

Answer 17

rate at which velocity changes; change in velocity/change in time; unit = m/s^2

Question 18

Deceleration

Answer 18

when an object slows down, its acceleration is opposite to the direction of its motion

Question 19

Instantaneous acceleration (a)

Answer 19

acceleration at a specific instant in time

Question 20

Free-fall

Answer 20

an object falling without air resistance or friction

Question 21

Acceleration due to gravity (g)

Answer 21

acceleration of free-falling objects; constant; ~ 9.8m/s^2

Question 22

Independent variable

Answer 22

horizontal axis on a graph

Question 23

Dependent variable

Answer 23

vertical axis on a graph

Question 24

slope (m)

Answer 24

rise/run; change in position/change in time = velocity; m of a graph of velocity vs. time = acceleration

Question 25

y-intercept (b)

Answer 25

point at which the line crosses the vertical axis