Motion Word Problems | MathHelp.com - By MathHelp.com
Transcript
| 00:01 | two cars leave from the same place at the same | |
| 00:03 | time and travel in opposite directions . One car travels | |
| 00:08 | at 55 mph and the other at 75 mph . | |
| 00:14 | After how many hours will they be ? 520 miles | |
| 00:17 | apart . Let's start this problem by setting up a | |
| 00:21 | diagram so that we can visualize what's going on . | |
| 00:25 | We have two cars starting from the same place and | |
| 00:31 | heading in opposite directions . They end up 520 miles | |
| 00:38 | apart . Mhm . If we use this arrow going | |
| 00:48 | to the left to represent the distance , the first | |
| 00:52 | car travels and the arrow going to the right to | |
| 00:55 | represent the distance the second car travels . Then you | |
| 01:00 | can see from the picture that the two distances will | |
| 01:04 | add to 520 miles . So setting up a little | |
| 01:08 | equation , we have the distance the first car travels | |
| 01:12 | , or D . One plus the distance the second | |
| 01:15 | car travels , or D . Two equals 520 . | |
| 01:23 | Now , let's set up a chart to organize the | |
| 01:25 | rest of the information in the problem . And we're | |
| 01:28 | going to base our chart on the formula that we | |
| 01:30 | talked about in the previous example , rate times time | |
| 01:34 | equals distance . Remember from your coin problems that the | |
| 01:43 | formula goes across the top of the chart . Right | |
| 01:50 | times time yeah . Equals distance down the left side | |
| 02:04 | . We have Our two cars , car one and | |
| 02:10 | car too . The rate for the first car is | |
| 02:15 | 55 mph . The rate for the second car is | |
| 02:21 | 75 mph . We don't know the time for each | |
| 02:26 | car , but we do know that since they leave | |
| 02:29 | at the same time , the two times are equal | |
| 02:33 | . So let's call the time for each car X | |
| 02:39 | . The distance for the first car will then be | |
| 02:42 | the rate of the first car times the time of | |
| 02:44 | the first car , which is 55 times x or | |
| 02:48 | 55 x . The distance for the second car will | |
| 02:52 | be the Ray , the second car times the time | |
| 02:55 | of the second car , which is 75 times x | |
| 02:59 | or 75 x . So these two values represent the | |
| 03:04 | distances for the two cars . And remember from our | |
| 03:08 | picture that the distance for the two cars will add | |
| 03:13 | to 520 so we can set up a little box | |
| 03:17 | down below and put 520 in it So that our | |
| 03:21 | equation will read 55 x Plus 75 x Equals 520 | |
| 03:33 | . And solving from here , we get X equals | |
| 03:37 | four , Since X represents the time for each car | |
| 03:43 | . In our chart , we know that our cars | |
| 03:46 | will be 520 miles apart after four hours . And | |
| 03:56 | that's our answer . |
Summarizer
DESCRIPTION:
OVERVIEW:
Motion Word Problems | MathHelp.com is a free educational video by MathHelp.com.
This page not only allows students and teachers view Motion Word Problems | MathHelp.com videos but also find engaging Sample Questions, Apps, Pins, Worksheets, Books related to the following topics.
GRADES:
STANDARDS:
