General Physics & Important Equations

Question 1

1. What are the base SI units for length, mass, and time?

Answer 1

Length: meter (m), Mass: kilogram (kg), Time: second (s).

Question 2

2. Name two derived SI units commonly used in physics.

Answer 2

Newton (N) for force, Joule (J) for work/energy (others include Watt (W), Pascal (Pa)).

Question 3

3. What is the difference between distance and displacement?

Answer 3

Distance is the total path traveled; displacement is the straight-line change in position, with direction.

Question 4

4. Define velocity and include its SI unit.

Answer 4

Velocity is the rate of change of displacement with direction; SI unit: meters per second (m/s).

Question 5

5. How is acceleration calculated?

Answer 5

a = Δv / Δt (change in velocity over time).

Question 6

6. State Newton’s First Law of Motion in simple terms.

Answer 6

An object remains at rest or moves uniformly unless acted on by an external force.

Question 7

7. State Newton’s Second Law of Motion.

Answer 7

F = m a (Force = mass × acceleration).

Question 8

8. State Newton’s Third Law of Motion.

Answer 8

Every action has an equal and opposite reaction.

Question 9

9. Give a real-world aviation example of Newton’s Third Law.

Answer 9

In a jet engine, hot exhaust gases are expelled backward, pushing the aircraft forward.

Question 10

10. Define weight and how it differs from mass.

Answer 10

Weight is the force due to gravity (W = m g), whereas mass is the amount of matter in an object.

Question 11

11. Write the formula for friction using μ (coefficient of friction).

Answer 11

F_friction = μ × F_normal.

Question 12

12. What is normal force?

Answer 12

A perpendicular contact force exerted by a surface on an object, balancing its weight (on a flat surface).

Question 13

13. Give a real-world example where friction is critical in aviation.

Answer 13

Aircraft tires rely on friction during landing to slow down on the runway.

Question 14

14. How is momentum defined?

Answer 14

p = m v (mass × velocity).

Question 15

15. What is impulse, and how does it relate to momentum?

Answer 15

Impulse = F × t = Δp (it’s the change in momentum).

Question 16

16. State the principle of conservation of momentum.

Answer 16

In a closed system, total momentum before an interaction equals total momentum after the interaction.

Question 17

17. Provide an aviation scenario where momentum is important.

Answer 17

During in-air refueling, the combined momentum of tanker + receiving aircraft remains conserved.

Question 18

18. Define work and give its formula.

Answer 18

Work W = F × d × cos(θ), where F is force and d is displacement.

Question 19

19. What is kinetic energy (KE)? Give the formula.

Answer 19

KE = ½ m v² (the energy of motion).

Question 20

20. Name a real-world aircraft example for kinetic energy.

Answer 20

An airplane at landing has large KE that must be dissipated by brakes/spoilers.

Question 21

21. What is potential energy (PE)?

Answer 21

Stored energy due to position or state, e.g., gravitational potential energy m g h.

Question 22

22. Give a real-world example of gravitational potential energy in aviation.

Answer 22

An aircraft at cruising altitude has large GPE that can be converted to KE during descent.

Question 23

23. Define power in mechanical terms.

Answer 23

Power (P) = Work / Time or F × v (rate of doing work).

Question 24

24. Why is power significant in aircraft performance?

Answer 24

An aircraft engine’s power output determines climb rate and overall performance.

Question 25

25. What does Hooke’s Law state?

Answer 25

F = k x (force = spring constant × extension/compression).

Question 26

26. Provide an aircraft example of Hooke’s Law.

Answer 26

Landing gear shock absorbers compress according to the applied force when the plane touches down.

Question 27

27. Explain stress and strain.

Answer 27

Stress = Force / Area, Strain = (Change in length) / (Original length).

Question 28

28. What is Young’s Modulus?

Answer 28

E = Stress / Strain, a measure of a material’s stiffness.

Question 29

29. Define pressure and give the formula.

Answer 29

P = F / A (force per unit area).

Question 30

30. State Pascal’s Principle.

Answer 30

A pressure applied to a confined fluid is transmitted equally in all directions.

Question 31

31. Give an aviation example of Pascal’s Principle.

Answer 31

Hydraulic systems (brakes, landing gear retraction) rely on fluid pressure transmission.

Question 32

32. What does Archimedes’ Principle describe?

Answer 32

An object in a fluid experiences buoyant force equal to the weight of fluid displaced.

Question 33

33. Provide a real-world example of Archimedes’ Principle.

Answer 33

A life vest increases buoyant force, helping a person float (or aircraft debris float after a ditching).

Question 34

34. State Bernoulli’s Principle in simple terms.

Answer 34

Faster fluid flow leads to lower pressure in that region of flow.

Question 35

35. How does Bernoulli’s Principle relate to aircraft lift?

Answer 35

Air moving faster over the wing’s curved surface lowers pressure on top, generating lift.

Question 36

36. Write the Continuity Equation for incompressible fluid flow.

Answer 36

A₁ v₁ = A₂ v₂ (cross-sectional area × velocity remains constant).

Question 37

37. What does Boyle’s Law state?

Answer 37

At constant temperature, for a fixed mass of gas, P ∝ 1 / V.

Question 38

38. State Charles’s Law.

Answer 38

At constant pressure, the volume of a gas is directly proportional to its temperature (in Kelvin).

Question 39

39. What is Gay-Lussac’s Law?

Answer 39

At constant volume, a gas’s pressure is directly proportional to its temperature (in Kelvin).

Question 40

40. Give the equation for the First Law of Thermodynamics.

Answer 40

ΔU = Q – W (change in internal energy = heat added – work done by the system).

Question 41

41. Define conduction, convection, and radiation briefly.

Answer 41

Conduction: heat via direct contact; Convection: heat via fluid movement; Radiation: heat via electromagnetic waves.

Question 42

42. What does Ohm’s Law state?

Answer 42

V = I R (voltage = current × resistance).

Question 43

43. In electrical circuits, what is electrical power?

Answer 43

P = V I (also I² R or V² / R).

Question 44

44. Give an aircraft example involving Ohm’s Law.

Answer 44

Designing lighting circuits in the cockpit, ensuring correct bulb current based on voltage and resistance.

Question 45

45. State Faraday’s Law of Induction.

Answer 45

An induced voltage (EMF) occurs when there is a change in magnetic flux through a conductor.

Question 46

46. What is Lenz’s Law?

Answer 46

An induced current flows in a direction that opposes the change causing it.

Question 47

47. Write the wave equation and define its terms.

Answer 47

v = f λ (velocity = frequency × wavelength).

Question 48

48. What is the Doppler Effect?

Answer 48

Change in frequency of a wave due to relative motion of source and observer.

Question 49

49. Give an aviation example using the Doppler Effect.

Answer 49

Radar systems measure aircraft or weather target speed by observing Doppler shifts in radio waves.

Question 50

50. Why is unit consistency (like using SI) crucial in physics calculations?

Answer 50

Mixing units causes errors; consistent units ensure correct, reliable results (vital in aircraft load, fuel, and performance calculations).