Physics Review Part 1

Topics on Twiz: significant figures, unit conversions, distance, speed and velocity (average,

r

continuous, instantaneous), d-t graphs (find distance, speed), d ! t graphs (find displacement, velocity), know how to analyze ticker tape.

v v !d v !d Be able to rearrange and use: v = and v = and !d and !d !t !t

Practice Significant Figures and Unit Conversions on the sheet I gave you Some Review Questions: Don’t forget to practice PROPER problem solving form! Use homework and quizzes too! 1. Define: distance, time, speed, instantaneous speed, constant speed, average speed, acceleration, distance, accurate, precise. v v v v 2. What do each of these variables represent? v, vav, Δv, t, Δd, v , vav , d , !d 3. Write down the formulas for each of the variables in #2 (don’t forget you have two ways to find time!) 4. Kathryn hates being late for class, so she sprints from her bus into the school. The distance from where her bus lets her off to her first class is 300 m . She runs for 60 s. a) What is her average speed in m/s? b) What is her average speed in km/h? 5. Lauren claims that she can run 7 m/s. How long would it take Lauren to run from Kathryn’s bus to the class(300 m)? 6. Valerie says that it only takes her 15 s to run from her bus stop. In gym class she can run at the same speed as Kathryn (see #5). What is the distance from Valerie’s bus to her first class? 7. During swim practice, Sarah’s distance and time followed the following table: Distance (m) 0.0 10.0 20.0 30.0 40.0 50.0

Time (s) 0.0 1.1 9.9 15.9 19.5 25.2

a. b. c. d.

Sarah’s distance-time graph What is her average speed? What is Sarah’s instantaneous speed at 30 s What does the graph look like when she stops for a break at the end of the length?

8. How long does it take for a motorboat travelling at 40km/h to cross a lake that is 2.0 km wide? 9. A Brett is training for a marathon. He runs 22 km[N] and then 32 km [S]. Assuming the entire run takes 4.2 h, answer the following questions: a) What is the runner’s position at the end of the run? b) what is the total displacement for the run? c) What is the average velocity? d) What is the total distance travelled? e) What is the average speed? PLUS the instantaneous and average speed/velocity from graphs from the homework. Answers:

1 – 3 check notes 4. a) 5 m/s b) 18 km/h 5. 42.8 s 6. 75 m 7. a) graph b) slope of LBF c) 1.9 m/s d) horizontal 8. 3 min 9. a) 10 km[S] b) 10 km[S] c) 2.4km/h [S] d) 54 km e) 13 km/h a) graph b) 0.50 m/s c) slope of tangent 10. a) graph b) slope of best fit c) area of triangle. 11. a) 4.0 m/s b) 0.15 m/s c) -63 m/s d) 5 m/s 12. A 2 m/s B 0 m/s C -2.5 m/s D 0 m/s E 4.4 m/s