Physics Review What do I need to know???

Variables Definition Types – Independent – Dependent

Graphing Parts of a graph – Axis labels Variables that go on each label Getting a straight line – y = mx + b m = slope b = y intercept

Graphing TimeDistance 0 s0 m 5 s15 m 15 s45 m If you are given data…. Graph it and then find the slope and intercept of the line

Pendulum Experiment Possible Variables – Length – Mass – Angle IV = your chosen variable DV = time (pendulum period) Variables that actually changed the period – Length

Pendulum Equation I will give it to you… Remember how to use it – What is the period of a pendulum with a length of 2 m? – What is the length of a pendulum that has a period of 2 seconds?

Vector vs. Scalar Scalar – Just a number, no direction. – Examples Speed Vector – Has both a direction and a magnitude. – Takes into account the direction and the magnitude. – Examples Acceleration and velocity

Speed Equation for speed – Speed = Δd/Δt A person walks 400 m in 2 minutes. What is their speed in m/s? How far does a person run if they walk at 7 mi/hr for 55 minutes?

Speed Calculations Speed is… – Total distance traveled = = 41 miles – Total Time = 33 minutes = 0.55 hours – Speed = 41 miles / 0.55 hrs = 75 mi/hr YumaEckleyWray 14 miles in 10 minutes 27 miles in 23 minutes

Velocity Equation for Velocity – Δd/Δt but…you have to take into account the direction Two types – Instantaneous At one specific time. – Average Over a period of time

Velocity Calculations Velocity is – Δd = 13 miles East – Δt = 41 minutes = 0.55 hrs – V = 13/ 0.55 = 24 mi / hr EAST YumaEckleyWray 14 miles in 10 minutes 27 miles in 23 minutes

Finding Velocity From a Graph Velocity is from the position vs. time graph. Find the average velocity… For 0-25 seconds For 0-10 seconds Find the instantaneous velocity for… 10 seconds 20 seconds

Acceleration Definition and Equation – ΔV /Δt Types – Instantaneous – Average

Finding Acceleration From a Graph Velocity is from the velocity vs. time graph. Find the average acceleration… For 0-15 seconds For seconds Find the instantaneous acceleration for… 10 seconds 20 seconds

How all the graphs relate On the board…

Significant Figures Know the rules – Before the numbers Doesn’t Count – Between the numbers Always Counts – After the Numbers After the decimal – Always counts Before the decimal – With a decimal (counts) – Without a decimal (doesn’t count)

Significant figures and Calculations The lower number of significant figures determines how many sig figs are in the answer x 100. = x 12 = 3.00 x =

Significant Figures and Sci. Notation Only significant numbers appear in the number part of scientific notation = 2.00 x 10. = 4.00 x 140 =

Metric Know the prefixes – Kilo, hecto, deca, deci, centi, milli 100 cm = _______ hm 1 kg = ________ cg

Conversions Always start with what you know over 1 Include Units Remember, if you want units to cancel out you have to have one on top of the fraction and one on the bottom of the fraction 1 mile = __________ inches 3 ft = __________ miles