Uniform Motion Uniform motion is when an object moves without changing its speed.
Solving Word Problems 1. Draw a sketch 2. Identify unknowns 3. Assign variable 4. Make a chart 5. Write and solve an equation
Equation for Motion Same Direction Distance for object one equals the distance for object two.
Example A helicopter leaves the airport going north at 180mph. Twenty minutes later a plane leaves and follows the helicopter at 330mph. How long does it take for the plane to pass the helicopter?
Helicopter Leaves first at 180 mph 20 minutes later 330mph 20 minutes later
Assign Variables Let t = Helicopter flight time ( to avoid fractions I use minutes) (t-20) Planes flight time
Make a Chart Who or What RATETIMEDISTANCEHelicopter Fast Plane
The helicopter flew for 44 minutes before the plane passes it. What was the question again? How long did it take the plane to pass the helicopter? Plane is (t-20) Helicopter is 24 minutes for the plane to pass 24 Minutes
Slow Smith 48 mph left at 8 am Fast Jones’ left 20 minutes later going 60 mph
Try This At 8 am, the Smith’s left the campground, driving slowly at 48 mph The Jones’ left the same campground and followed the same route, driving faster at 60 mph. At what time did the Jones’ overtake the Smith’s?
Make a Chart Who or What RATETIMEDISTANCE Slow Smiths Fast Jones’
Great t= 100 min The Smiths drove for 100 minutes.100/60 is 1hr 40 min. Is that the question? At what time did the Jones’ overtake the Smith’s? The Smith left at 8 am plus 1 hr and 40 min. The Jones’ passed at 9:40am