Science Review Conceptual Physics Chapters 1-8

Scientific Notation Form – #.### x 10 exp – #s are all significant figures Exponents – Negative for # between 0 & 1 – Zero as the exponent for #s 1 to … – Positive for # of 10 or higher Rule of exponents: (10 A )(10 B ) = 10 A+B (10 A )/ (10 B ) = 10 A-B

Significant Figures All #s 1–9 All zeros between # 1-9: 409; All zeros after #s 1-9 after the decimal point – 19.00; Rules: – Product or Quotient has no more S.F. than the least # of S.F. in the problem – Sum or Difference has no more decimal places than the least # decimal places in the problem

SI units Value, Symbol, & Name o 10 9 = G = giga = M = mega- o 10 3 = k = kilo = h = hecta- o 10 1 = da = deca = d = deci- o = c = centi = m = milli- o =  = micro = n = nano- o = p = pico-

SI Base Units & Derived Units Mass (kilogram); Length (meter); Temperature (Kelvin); Time (second); Current (ampere); Luminosity (candella) Derived units have more than 1 SI base unit – Velocity (m/s); Volume (Liter; cm 3 ); Force (N); Density (kg/cm 3 ); Acceleration (m/s 2 ); Area (m 2 ); Pressure (Pa) …

Scientific Method Steps – Observation: senses & technology – Form hypothesis: proposed explanation – Gather information: people, publications, Internet – Plan & perform experiment: constants, control, independent variable, & dependent variable – Record & analyze data: statistics, graph, chart, words – Conclude &/ or modify hypothesis – Support or disagree with standing theory

Measurements & Calculations Quantitative vs. Qualitative: #s vs. words Precision vs. Accuracy: grouping vs. accepted # Science vs. Technology Science- answer theoretical questions Technology- solve practical problems

Mechanical Equilibrium Force is a push or a pull Equilibrium Rule:  F = 0 – Sum of all forces equals zero Static equilibrium – objects at rest Dynamic equilibrium – objects moving in a straight line at a constant speed

Vector vs. Scalar Quantities Vector – Magnitude – Direction Parallelogram Rule – Resultant = diagonal of constructed parallelogram – Hypotenuse = (√2)(a) of square = √c 2 of a 2 +b 2 =c 2 Scalar – Magnitude only (time, speed, distance, weight …)

Newton’s Laws of Motion 1 st Law = Law of Inertia – What’s stopped stays stopped; what’s moving stays moving. 2 nd Law = Objects accelerate when a net force acts on it; acceleration =  velocity/ time – Unbalanced forces cause acceleration (+ or -) – Mass resists acceleration 3 rd Law = Action forces are equal & opposite to reaction forces.

Newton’s 1 st Law of Motion Inertia- Objects resist change in motion – Force causes changes in motion Newton is SI unit of force; N = (kg)(9.8 m/s 2 ) – Friction prevents continued motion – Mass is a measure of inertia (Weight is force of gravity) – Objects continue at rest or at a constant speed in a straight line.

Newton’s 2 nd Law of Motion Acceleration produced by a net force is – Directly proportional to magnitude of force – In the same direction as the net force – Inversely proportional to the mass of object Acceleration = net force/ mass Force = (mass)(acceleration) a = N/ kg = (kg m/ s 2 )/ kg = meter/ second 2

Newton’s 3 rd Law Reaction is equal & opposite to action forces Force and Mass with Acceleration – force/ mass = acceleration – Lighter object accelerate faster with same force. Lift – Downward thrust of air causes object to rise. Defined System – Action & reaction forces only cancel each other out if they are in the same system.

Linear Motion Motion is relative – Object moves if position changes relative to a fixed point Speed is scalar Velocity & acceleration: vector quantities Free Fall – Acceleration =  velocity/ time interval = 9.8 m/s 2 – Distance = ½ (9.8 m/s 2 )(time elapsed) 2 = ½ g t 2 = d – Terminal speed when air resistance = g – Air resistance force ~ (speed)(frontal area)

Projectile Motion Described by horizontal & vertical vectors – Are independent of one another – Vertical component = gravitational acceleration Diagonal=resultant of 2 perpendicular vectors Components = 2 perpendicular vectors that add up to a given vector Resolution = process of finding components

Momentum Momentum = mass x velocity; p = m v Impulse changes momentum – Impulse = force x time interval; Ft =  (mv) – Bouncing increases momentum. Conservation of momentum – Elastic collisions: no permanent deformation & no heat generated – Inelastic collisions: real life collisions