Aim: How do we solve motion problems involving one object.

Homework: Complete Handout sheet both sides

Lesson Review:

Example problem: How far can a man drive out into the country at the average rate of 40 mph and return over the same road at the average rate 30 mph if he travels a total of 7 hours?
Need to find T then substitute in RT to find distance in D=RT

Tout + T back = 7 hrs and Distance out is same as the Distance back

Tout + Tback = 7hrs.
Let Tout = X
X +Tback = 7hrs
subtract X from both sides:
Tback = 7hrs - X
So: T out = X and T back = 7-X

Dout = RT = 40mph x X
Dback = RT 30mph x (7-X)
If Dout = Dback
Then 40X = 30 (7-X)
40X = 210 -30X
40X + 30X =210
70X = 210
X=3 hrs
Dout = RT = 40(3) = 120 miles
as a check Dout should = Dback
Dback = RT = 30 (7-x) = 30(7-3) = 30(4) = 120 miles

Practice Exercise:http://kutasoftware.com/FreeWorksheets/Distance%20Rate%20Time%20Word%20Problems.pdf