4.8 Rate-Time-Distance Problems

• Objective: To solve some word problems involving uniform motion.

o Warm – up: Motion in the Opposite Direction.Mary Beth and Michael leave school traveling in opposite directions. Michael is walking and Mary Beth is biking, averaging 6 km/h more than Michael. If they are 18 km apart after 1.5 h, what is the rate of each?rate time distance

Mary Beth

Michael

4.8 Rate-Time-Distance Problems

Motion in the Same Direction.o A helicopter leaves Central

Airport and flies north at 180 mi/h. Twenty minutes later a plane leaves the airport and follows the helicopter at 330 mi/h. How long does it take the plane to overtake the helicopter?

o Carla begins biking south at 20 km/h at noon. Dean leaves from the same point 15 min later to catch up with her. If Dean bikes at 24 km/h, how long will it take him to catch up with Carla?

rate time distance

helicopter

plane

rate time distance

Carla

Dean

4.8 Rate-Time-Distance Problems

Motion of a Round Trip.o A ski lift carried Maria up a

slope at the rate of 6 km/h, and she skied back down parallel to the lift at 34 km/h. The round trip took 30 min. How far did she ski and for how long?

o Mark drove his car to the garage at 48 km/h and then walked back home at 8 km/h. The drive took 10 min less than the walk home. How far did Mark walk and for how long?

rate time distance

Up

down

rate time distance

To garage

Back home

4.8 Rate-Time-Distance Problems

• Homework:– Pg. 170

Written Exercises #2, 4, 6, 9, 3, 8, 10