1. Solving Word Problems To solve a word problem, think: numbers, question, formula, label circle the numbers, read the question, write the formula and finally label the parts of the question that relate to the formula

2. Solving Word Problems – cont’d Let’s do a sample for density – follow the prompts A sample of substance X has a density of 5 g/ml and a mass of 80 g. What is it’s volume? ---------------------------------------------------------------- numbers question formula label Then, solve the equation. Volume = 80 g / 5 g/ml Volume = 16 ml Density = Mass / Volume Volume = Mass / Density mass density

3. MOTION Describing How Things Move

4. Motion Also called Kinematics Measured as a change in position Distances can be positive or negative Depends on the “frame of reference”

5. Frame of Reference Described by the observer Compares speeds and angles to the observer’s surroundings Explains the 75mph fly

6. Speed How rapidly an object changes location Described in units of distance divided by units of time Miles per hour Kilometers per hour Centimeters per month

7. Speed Formula V speed = t time d distance V speed d distance t time

8. What is the speed of a runner that travels 250m in 50min.? 1. 5 m/min. 2. 0.2 m/min. 3. 12,500 m/min.

9. How long does a trip of 3000 km take if you travel at 110 km/hr.? 1. 330000 hr. 2. 0.037 hr. 3. 27 hr.

10. How far will a car traveling at 70km/hr. go in 2 hours? 1. 360 km 2. 140 km 3. 0.4 km 4. 2.5 km 5. 0.04 km

11. Average human walking speed is 5 km/hr. How far can you walk in two hours? 1. 10 km 2. 10 km/hr. 3. 10 hr. 4. 10 kmhr. 5. None of the above

12. What is the speed of a bike that travels 12 km in 30 min.? 1. 360 km/hr 2. 24 km/hr 3. 0.4 km/hr 4. 2.5 km/hr 5. 0.04 km/hr

13. Three Kinds of Speed

14. Speed 1) What is the average speed of a cheetah that sprints 100 m in 4 s? How about if it sprints 50 m in 2 s? 2) If a car moves with an average speed of 60 km/h for an hour, it will travel a distance of 60 km. (a) how far would it travel if it moved at this rate for 4 h? (b) for 10 h?

15. Speed 2 3) In addition to speedometer on the dashboard of every car is an odometer, which records the distance traveled. If the initial reading is set at zero at the beginning of a trip and the reading is 40 km one half hour later, what has been your average speed? 4) Would it be possible to attain the average speed in previous example and never go faster than 80 km/h?

16. Velocity Velocity describes the speed and the direction of motion

17. Instantaneous Velocity

18. Speed or Velocity? 186,282 mi. / s 107 km / h North 55 mi. / h 1300 km / h East 212 mi. / h

19. Velocity With what is the race-car driver concerned, speed or velocity? The speedometer of a car moving to the east reads 100 km/h. It passes another car that moves to the west at 100 km/h. Do both cars have the same speed? Do they have the same velocity? During certain period of time, the speedometer of a car reads a constant 60 km/h. Does this indicate a constant speed or a constant velocity?

20. Velocity How might you estimate your speed if the speedometer in your car is broken? Which of the following can be used to measure an average speed: stopwatch, odometer, or speedometer? An instantaneous speed?