Chapter 1 #3

Question 1

What is the definition of a Physical Quantity?

Answer 1

A physical quantity is any physical property that can be measured and consists of a magnitude and a unit.

Question 2

List the 7 Fundamental (Base) Quantities and their SI Units.

Answer 2

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

Question 3

What is the relationship between degrees Celsius (°C) and Kelvin (K)?

Answer 3

0°C = 273 K. The SI base unit of temperature is Kelvin, not degrees Celsius.

Question 4

Which is the only SI base unit that includes a prefix in its name?

Answer 4

The kilogram (kg).

Question 5

What is a Derived Unit?

Answer 5

A unit derived from a combination of the fundamental base units.

Question 6

What are the SI base units for Force (Newtons)?

Answer 6

kg m s^-2.

Question 7

What are the SI base units for Pressure (Pascals)?

Answer 7

kg m^-1 s^-2.

Question 8

What are the SI base units for Energy or Work (Joules)?

Answer 8

kg m^2 s^-2.

Question 9

What are the SI base units for Power (Watts)?

Answer 9

kg m^2 s^-3.

Question 10

What are the SI base units for Electric Potential / Voltage (Volts)?

Answer 10

kg m^2 s^-3 A^-1.

Question 11

What are the SI base units for Electric Charge (Coulombs)?

Answer 11

A s.

Question 12

What are the SI base units for Resistance (Ohms)?

Answer 12

kg m^2 s^-3 A^-2.

Question 13

What does it mean for an equation to be Homogeneous?

Answer 13

The units on both sides of the equation are identical.

Question 14

What are the 4 steps to find the SI base units of a derived quantity?

Answer 14

1. Break into fundamental quantities. 2. Replace with base units. 3. Remove unitless constants. 4. Simplify.

Question 15

In the equation v = T^p μ^q, if kg appears on the right side but not left, what does this imply about p and q?

Answer 15

Their powers must cancel: p + q = 0.

Question 16

Is the constant g unitless?

Answer 16

No. g has units of acceleration: m s^-2.

Question 17

Multiplying factors for Peta, Tera, Giga.

Answer 17

Peta: 10^15; Tera: 10^12; Giga: 10^9.

Question 18

Multiplying factors for Mega and Kilo.

Answer 18

Mega: 10^6; Kilo: 10^3.

Question 19

Multiplying factors for Micro, Nano, Pico, Femto.

Answer 19

Micro: 10^-6; Nano: 10^-9; Pico: 10^-12; Femto: 10^-15.

Question 20

Define Scalar quantity and give examples.

Answer 20

Quantity with magnitude only. Examples: distance, speed, mass, time, energy, work, power, pressure.

Question 21

Define Vector quantity and give examples.

Answer 21

Quantity with magnitude and direction. Examples: displacement, velocity, acceleration, force, weight, momentum, torque.

Question 22

How are vectors represented visually?

Answer 22

A line with an arrow; length shows magnitude; arrow shows direction.

Question 23

How do you arrange vectors to find the resultant?

Answer 23

Arrange them head-to-tail.

Question 24

How do you calculate vector subtraction (A – B)?

Answer 24

Reverse B and add it to A.

Question 25

What does it mean if a vector diagram forms a closed triangle?

Answer 25

The object is in equilibrium.

Question 26

In the cosine rule for resultant, which angle do you use?

Answer 26

The angle between the vectors arranged head-to-tail.

Question 27

Component adjacent to angle θ of force F?

Answer 27

Fx = F cosθ.

Question 28

Component opposite angle θ of force F?

Answer 28

Fy = F sinθ.

Question 29

Maximum possible resultant of forces?

Answer 29

Add all forces.

Question 30

Minimum possible resultant of forces?

Answer 30

Subtract smaller forces from the largest.

Question 31

Constant speed implies what about forces?

Answer 31

The body is in equilibrium.

Question 32

Full name of symbol g?

Answer 32

Acceleration due to gravity / gravitational field strength / free fall acceleration.