1. 8-5 Motion d=rt 9P9: Interpret systems

2. Types of motion Problems T1) Distance covered is equal (d = d) T2) Distance covered is equal + wind or current (d = d) T3) Different distance – same direction (d – d = d apart ) T4) Different distance – Opposite direction (d + d = d total ) Steps -Draw picture to identify type -Make r*t = d table -Write equation -Solve - Interpret answer

3. T1) A train leaves Slaton travelling east at 60 km/hr. An hour later, another train leaves on a parallel track at 80 km/hr. How far from Slaton will the trains meet? How long did each travel? rtd A B = d s = d f (substitute) 60t = 80(t-1) 60t = 80t – 80 -20t = -80 t = 4 The slow train travelled 4 hrs the faster train travelled 3 hours dfdf = = t t-180 60dsds Now we can find distances also!

4. T2) A motorboat took 3 hours to make a downstream trip with a current of 6 mph. The return trip took against the same current took 5 hours. Find the speed of the boat and how far it travelled. rtd down back b+6 b-6 3 5 d down d up d down = d up Using substitution (b+6)(3) = (b-6)(5) solve 3b +18 = 5b -30 48 = 2b 24 = b The boat’s speed is 24 mph = = =

5. T3) Two cars leave town at the same time in the same direction. One travels 35mi/hr and the other travels 40 mi/hr. In how many hours will they be 15 miles apart? How far did each travel? rtd A slow B fast = = = d f – d s = d apart (substitute) 40t - 35t =15 5t = 15 t = 3 d s = 35(3) d f = 40(3) = 105 miles = 120 miles 35 40t t dfdf dsds They travelled same amount of time

6. T4) Two cars leave town at the same time going opposite directions. One of them travels 60 mi/h and the other 30 mi/hr. In how many hours will they be 150 miles apart? rtd A B = = =t t 30 60dfdf dsds d f + d s = d total 60t + 30t =150 90t = 150 Now we can substitute that back in to find the distances

7. Day 1: 8-5/384/ 4-9 Day 2: 8-5/384/ 10-19, 23-29