Motion Word Problems Students will solve motion problems by using a Guess & Check Chart and Algebra D = R x T Review Motion Problems use the formula Distance = Rate x Time If the rate is 60 mph and the time is 3 hours, what is the distance? If the distance is 300 miles and it took 4 hours, what was the rate of speed? If the distance is 200 miles and the rate is 40 mph, what is the time? If the time was 2.5 hours and the rate was 40 mph, what was the distance? What’s involved in a motion problem? Two vehicles A slower one And a faster one! What’s involved in a motion problem? Going in the same direction. Or opposite directions!! What’s involved in a motion problem? Leaving at the same time. Leaving at different times Step One: Draw the problem It helps to find the distance needed to solve the problem. Look for: Starting Point,Direction, Departure Time Draw: Ex 1. Two cars start at the same point, at the same time, and travel in opposite directions. The slow car travels at 56 mph and the fast car travels at 60 mph. In how many hours, will they be 464 miles apart? Slow Car (56 mph) Fast car (60 mph) Slow Car Distance + Fast Car Distance = 464 Drawing Practice Ex. 2 Two trains start at the same time from stations that were 360 miles apart and travel towards each other. The rate of the fast train exceeded the rate of the slow train by 10 miles per hour. At the end of 2 hours, the trains were still 120 miles apart. Find rate of each train. Starting Pt: 360 miles apart. Direction: Towards each other Starting Time: Same Fast Train 120 miles Slow Train Total Distance: 360 miles Fast Distance + Slow Distance + 120 = 360 or Fast Distance + Slow Distance = 240 Drawing Practice Ex 3. How far can a man drive out into the country at the average rate of 60 miles per hour and return over the same road at 45 miles per hour if he travels a total of 7 hours. Starting Pt: Home & Unknown Direction: Away and back home Starting Time: A total of 7 hours Fast Rate Slow Rate Fast Distance = Slow Distance Step 2: Make A Chart Slow Slow Slow Fast Fast Fast Distance Rate Time Dist Rate Time Dist Equation Ex 1. Two cars start at the same point, at the same time, and travel in opposite directions. The slow car travels at 56 mph and the fast car travels at 60 mph. In how many hours, will they be 464 miles apart? Fill in: What you know Slow Rate Slow Time Slow Dist Fast Rate Fast Time Fast Dist Distance Equation SD + FD = 464 56 60 Which is the “GUESS” column? Hours Ex 1. Two cars start at the same point, at the same time, and travel in opposite directions. The slow car travels at 56 mph and the fast car travels at 60 mph. In how many hours, will they be 464 miles apart? Guess: 2 hours and fill in rest of chart Slow Rate Slow Time Slow Dist Fast Rate Fast Time Fast Dist Distance Equation SD + FD = 464 56 2 112 60 2 120 112+120 = 232 No Ex 1. Two cars start at the same point, at the same time, and travel in opposite directions. The slow car travels at 56 mph and the fast car travels at 60 mph. In how many hours, will they be 464 miles apart? Try more Guesses Slow Slow Slow Fast Fast Fast Rate Time Dist Rate Time Dist 56 2 112 60 2 120 56 5 280 60 5 300 56 4 224 60 4 240 Distance Equation SD + FD = 464 112+120 = 232 No 280+300=580 No 224+240=464 YES! IN 4 HOURS, THEY WILL BE 464 MILES APART Using Algebra Use Guess & Check Chart to convert to an Algebra problem Place x in Guess Column. Fill in rest of row Define variables Write & Solve Equation Answer Question! Ex 1. Two cars start at the same point, at the same time, and travel in opposite directions. The slow car travels at 56 mph and the fast car travels at 60 mph. In how many hours, will they be 464 miles apart? Slow Slow Slow Fast Fast Fast Rate Time Dist Rate Time Dist 56 4 224 60 4 240 56 X 56x 60 X 60x Let x = # of hours Distance Equation SD + FD = 464 224+240=464 YES! 56x+60x=464 56x+60x=464 116x=464 X=4 Answer: It took four hours. Ex. 2 Two trains start at the same time from stations that were 360 miles apart and travel towards each other. The rate of the fast train exceeded the rate of the slow train by 10 miles per hour. At the end of 2 hours, the trains were still 120 miles apart. Find rate of each train. Fill in what you know and find Guess Column Slow Slow Slow Fast Fast Fast Distance Rate Time Dist Rate Time Dist Equation SR+10 2 SD+FD=240 2 Guess: Slow Rate Fast Rate = Slow Rate + 10 Ex. 2 Two trains start at the same time from stations that were 360 miles apart and travel towards each other. The rate of the fast train exceeded the rate of the slow train by 10 miles per hour. At the end of 2 hours, the trains were still 120 miles apart. Find rate of each train. KEEP GUESSING Slow Slow Slow Fast Fast Fast Distance Rate Time Dist Rate Time Dist Equation SR+10 SD+FD=240 50 2 100 60 2 120 100+120=220 60 2 120 70 2 140 120+140=260 55 2 110 65 2 130 110+130=240 Slow Train Rate: 55 Fast Train: 65 Ex. 2 On to ALGEBRA X is in Guess column SR ST SD FR FT FD SR+10 55 X 2 2 110 65 2 2X X+10 2 Dist Equ SD+FD=240 130 110+130=240 2(X+10) 2X+2(X+10)=240 Let x = slow rate 2x+2(x+10) = 240 Let x + 10= Fast rate 2x + 2x + 20 = 240 Answer: Slow Train: 4x+20 = 240 55 mph 4x = 220 Fast Train: X = 55 65 mph Ex 3. How far can a man drive out into the country at the average rate of 60 miles per hour and return over the same road at 45 miles per hour if he travels a total of 7 hours. Fill in what you know and find Guess Column Slow Slow Slow Fast Fast Fast Distance Rate Time Dist Rate Time Dist Equation SD=FD Guess: Slow Time Slow Time + Fast Time = 7 Ex 3. SR ST SD FR FT FD Distance Equation SD=FD 45 45 45 45 5 4 3 X 225 180 135 45x 60 60 60 60 2 3 4 (7-x) 120 180 240 60(7-x) 225=120 180=180 135=240 45x=60(7-x) Let x = Slow Time 45x=60(7-x) Answer the Question! 45x=420-60x Let 7-x = Fast Time 105x=420 The man drove out 180 miles X=4 Wrapping It UP- Motion Distance Formula : D=rxt Why is it necessary to draw picture? To find Distance Equation Where does the x go in the Guess and Check chart? In the Guess column