UNIT 1 STUDY GUIDE

A comprehensive set of practice questions/answers drawn from the lecture notes, covering the scientific method, fundamental physics concepts, energy, momentum, thermodynamics, and measurement systems.

What are the five key steps of the scientific method as listed in the notes?

Observation, hypothesis, experimentation, analysis, and conclusion (with the process often looping back to refine the hypothesis).

How is a hypothesis defined in the notes?

A proposed, testable explanation for an observation; the starting point of an investigation.

What is a scientific theory according to the notes?

A well-substantiated, comprehensive explanation for a broad set of observations, repeatedly tested and verified by evidence (e.g., the Theory of Evolution).

What is a scientific law according to the notes?

A description of a consistent pattern or relationship in nature, often expressed mathematically; describes what happens but not why.

What is the Ptolemaic (Geocentric) Model?

Earth-centered model using epicycles to explain planetary motion, especially retrograde motion.

What is the Copernican (Heliocentric) Model?

Sun-centered model that provides a simpler explanation for planetary movements.

What is Kepler’s Law of Ellipses?

Planets orbit the Sun in ellipses with the Sun at one of the focal points.

What is Kepler’s Law of Equal Areas?

A planet sweeps out equal areas in equal times, so its speed varies along the orbit.

Who provided the precise observations that helped Kepler formulate his laws?

Tycho Brahe.

What is Newton’s First Law (Inertia)?

An object at rest stays at rest and a moving object stays in motion unless acted on by a net external force.

What is Newton’s Second Law?

The net force on an object equals its mass times its acceleration (F_net = m a).

What is Newton’s Third Law?

For every action, there is an equal and opposite reaction.

What is the difference between mass and weight?

Mass is the amount of matter (constant); weight is the gravitational force on that mass (depends on location).

What is the difference between speed and velocity?

Speed is how fast you’re going; velocity includes speed and direction.

What is acceleration?

Any change in velocity—speeding up, slowing down, or turning.

What is the formula for work?

W = F d cos(theta); units are joules (J).

What is energy in the context of these notes?

The ability to do work; energy exists in multiple forms and is linked to work and motion.

What is kinetic energy and its formula?

Energy of motion; KE = 1/2 m v^2 (velocity appears squared).

What is gravitational potential energy and its formula?

Energy due to position in a gravitational field; Ug = m g h (relative to a reference level on Earth).

What does the Work-Energy Theorem state?

Work is related to changes in kinetic energy: W = ΔK.

What is a simple machine and what is Mechanical Advantage (MA)?

A device that changes the magnitude of the force; MA = Fout / Fin; in an ideal machine, input work equals output work.

What is the MA for a lever?

MAlever = din / dout = Fout / F_in.

What is the MA for an inclined plane?

MA_inclined = L / h (length of slope over height).

What is the unit of heat and the relation Q = m c ΔT?

Heat is energy transfer due to temperature difference; Q = m c ΔT, where c is the specific heat capacity.

What is the approximate specific heat capacity of water?

About 4.184 kJ/(kg·°C) (often approximated as 4.2 kJ/(kg·°C)).

What are the two main phase-change energies for water?

Heat of fusion: 335 kJ/kg (solid to liquid); Heat of vaporization: 2260 kJ/kg (liquid to gas).

How do evaporation and boiling differ?

Evaporation occurs at the surface at any temperature; boiling occurs throughout the liquid at its boiling point.

What is sublimation?

Solid to gas phase change, occurring under the right temperature and pressure (e.g., dry ice at certain conditions).

What do the first and second laws of thermodynamics state in brief?

First law: energy is conserved; Second law: not all heat can be converted into work and entropy tends to increase in isolated systems.

What is entropy?

A measure of a system’s disorder; higher entropy means more disorder.

What does mass-energy equivalence say?

E = m c^2; mass and energy are interchangeable; even a small mass contains enormous energy.

What are linear and angular momentum?

Linear momentum p = m v; angular momentum L = I ω; momentum is conserved without external forces; angular momentum is conserved without external torques.

What is rotational inertia and how does it affect spinning?

Rotational inertia I depends on mass distribution; moving mass closer to the axis lowers I, causing angular velocity to increase (conservation of angular momentum).

What is centripetal force?

The inward force required to keep an object moving in a circle; the outward feeling is due to inertia.

What is buoyancy and Archimedes’ Principle?

Buoyant force Fb = ρfluid Vdisplaced g; an object floats if buoyant force is equal to or greater than its weight.

What is density and how is it defined?

Density ρ = m/V; measured in kg/m^3; crucial for buoyancy and material identification.

What is pressure in fluids and its basic relation?

Pressure P = F/A; increases with depth in a fluid; pressurized systems transmit force via fluids.

What is the inverse-square nature of gravity?

Gravitational force decreases with the square of the distance between masses: F ∝ 1/r^2.

What is the minimum orbital speed formula for a satellite around a planet?

v = sqrt(G M / r) where G is the gravitational constant, M is the planet’s mass, and r is the orbit radius.

What are the two key postulates of Special Relativity?

1) The speed of light is the same for all observers; 2) The laws of physics are the same in all inertial frames.

What are the seven SI base units?

Length (meter, m); Mass (kilogram, kg); Time (second, s); Electric current (ampere, A); Thermodynamic temperature (kelvin, K); Amount of substance (mole, mol); Luminous intensity (candela, cd).

What are two important energy-related notes about civilization’s energy sources?

The Sun is the ultimate energy source; fossil fuels are finite; renewable sources like solar require storage and infrastructure.

What is the difference between temperature and heat, as summarized in the notes?

Temperature measures average kinetic energy; heat is the transfer of thermal energy between objects due to a temperature difference.

What is the basic idea behind the energy transformations discussed in heat engines?

Heat flows from hot to cold; a portion can be converted to work, but some energy is always wasted as heat to the surroundings.