Definitions 1: Measurements, Kinematics

Question 1

Physical Quantity

Answer 1

A property of a material or system that can be quantified by measurement. Each quantity consists of a numerical magnitude and a unit.

Question 2

SI Units

Answer 2

Mass: Kilogram (kg)
Length: Metre (m)
Time: Second (s)
Electric Current: Ampere (A)
Temperature: Kelvin (K)
Amount of substance: Mole (mol)
Luminous Intensity: Candela (cd)

Question 3

Homogenous Equation

Answer 3

All the terms on both sides of the equation have the same base units.

Question 4

Dimensionless Quantity

Answer 4

A quantity does not have an associated physical dimension and is purely a number.

Question 5

Prefixes:
Tera, T:
Giga, G:
Mega, M:
Kilo, k:

Deci, d:
Centi, c:
Milli, m:
Micro, µ:
Nano, n:
Pico, p:

Answer 5

Tera, T: 10^12
Giga, G: 10^9
Mega, M: 10^6
Kilo, k: 10^3

Deci, d: 10^-1
Centi, c: 10^-2
Milli, m: 10^-3
Micro, µ: 10^-6
Nano, n: 10^-9
Pico, p: 10^-12

Question 6

Order of magnitude

Answer 6

The power of ten exponent of the numerical value.

Question 7

Random error

Answer 7

When the measured readings are scattered about the true value with no fixed pattern.

Question 8

Systematic Error

Answer 8

Results in measurements that are constantly larger or constantly smaller than the true values.

Question 9

Accuracy

Answer 9

Determined by the closeness of the values to the true values.

Question 10

Precision

Answer 10

Determined by the range in the values.

Question 11

Uncertainty

Answer 11

The total range of values on both sides of a measurement in which the actual value of the measurement is expected to lie.

Question 12

Fractional Uncertainty

Answer 12

The ratio of absolute uncertainty to the measured value of a quantity.

Question 13

Percentage Uncertainty

Answer 13

The fractional uncertainty expressed in percentage form.

Question 14

Scalar

Answer 14

A physical quantity that has magnitude only.

Question 15

Vector

Answer 15

A physical quantity that has both magnitude and direction.

Question 16

Distance

Answer 16

The total length of the actual path travelled between start and finish points.

Question 17

Displacement

Answer 17

The straight line distance from start point to finish point, in that direction.

Question 18

Speed

Answer 18

The rate of change of distance.

Question 19

Average Speed

Answer 19

The distance travelled over time between the start and finish points.

Question 20

Velocity

Answer 20

The rate of change of displacement.

Question 21

Average Velocity

Answer 21

The displacement over the time taken between the start and finish points.

Question 22

Acceleration

Answer 22

The rate of change of velocity.

Question 23

Average Acceleration

Answer 23

The change in velocity over the time taken between the start and finish points.

Question 24

Kinematics Equations
(Constant acceleration, s=0 when t=0, for motion in a straight line)

Answer 24

v = u + at
s = (1/2)(u + v)(t)
s = ut + (1/2)at^2
v^2 = u^2 + 2as