Section 4.8

Rate-Time-Distance Problems

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What is uniform motion?

Motion without a change in speed/rate

Uniform Motion Problems

D r t

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Type of Problem Key to Solving

Opposite Direction (toward or away) Distances add to a total.

Same Direction (catch-up) Distances are equal.

Same Direction (two-part trip) Distance add to a total.

Round Trip Distances are equal.

Three Types of Problems

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Rate X Time= Distance

Brent

Jane

Example 1 Bicyclists Brent and Jane started at noon from points 60 km apart and rode toward each other, meeting at 1:30 PM. Brent’s speed was 4 km/hr greater than Jane’s speed. Find their speeds.

What type of problem is this? Add or Equal?

Equation: (see text book)

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Example 2: A helicopter leaves Central Airport and flies north at 180 mi/hr. Twenty minutes later a plane leaves the airport and follows the helicopter at 330 mi/hr. How long does it take the plane to overtake the helicopter?

What type of problem is this? Add or Equal?

Rate X Time= Distance

Helicopter

Plane

Equation: (see text book)

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Example 3: A ski lift carried Maria up a slope at the rate of 6 km/hr, and she skied back down parallel to the lift at 34 km/hr. The round trip took 30 minutes. How far did she ski and for how long?

What type of problem is this? Add or Equal?

Rate X Time= Distance

Up

Down

Equation: (see text book)

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Assignment

SEE SYLLABUS