2016/8/29 Significant figures Scientific notation Dimensional analysis Physics 111 SI 2016/8/29 Significant figures Scientific notation Dimensional analysis

Questions?

Sessions setup Mondays: Review and preview with PowerPoint outline Tuesdays: Worksheets and open for in-session questions Wednesdays: Worksheets and open for in-session questions Session ppts and answer keys to worksheets won’t be uploaded on PHYS 111 SI website

Significant figures How many significant figures do these numbers have? 1) 3.1415926 2) 0.5334 3) 2500 If you are solving a question that has 2.7s and 6.23m in the question itself, how many significant figures you need to put in your answer?

Significant figures Nonzero digits are always significant Any zeros between two significant digits are significant A final zero or trailing zeros in decimal portion are significant

Scientific notation Put the prefixes on your “cheat sheet” Let’s write some numbers into scientific notation: 1) 0.00732 2) 3590000 4) 0.020098

Dimensional analysis Trigonometric functions

Dimensional analysis We need to set up a coordinate system before describe any motion What are the two things to do to set up a coordinate system? 1) Define the origin 2) Define the positive direction

Dimensional analysis What is the difference between vector and scalar quantities?

Dimensional analysis What is the slope in this two types of graphs? 1) Graph of position as a function of time (x vs. t) Slope = velocity 2) Graph of velocity as a function of time (v vs. t) Slope = acceleration

Dimensional analysis Do you still remember this question from lecture? A quick trick for conceptual problems like this: Assign actual values (e.g.: -3m/s) according to the conditions in the question