In the illustration, pieces #31 and #29,...

Question 1 of 270705eccefa3bacbc34ba4d47d6d

In the illustration, pieces #31 and #29, have 16 and 55 teeth respectively. In order to start the engine, the Bendix drive must turn 3000 RPM. Therefore, the air motor assembly must rotate at __________. See illustration MO-0044.

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Question 1 of 27070

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🔍 Key Concepts

• Gear ratio between two meshing gears (speed is inversely proportional to number of teeth) • Relationship: speed × teeth = constant for a gear pair: $N_1 T_1 = N_2 T_2$ • Which gear in the illustration is physically connected to the Bendix drive versus the air motor shaft

💭 Think About

• From the illustration, decide which numbered gear (#29 or #31) is on the air motor shaft and which one turns with the Bendix drive shaft. • Once you know which gear must be at 3000 RPM, set up the proportion using their tooth counts (16 and 55) to solve for the unknown speed. • After finding the theoretical RPM from your ratio, compare it carefully to the multiple-choice options, paying attention to whether the motor should turn faster or slower than the Bendix drive in a starter system.

✅ Before You Answer

• Be sure you assign the 16 teeth and 55 teeth to the correct parts (#31 and #29) exactly as stated in the problem. • Confirm which component (air motor vs. Bendix drive) you’re solving for so you put the 3000 RPM on the correct side of your equation. • Double-check your math: when you increase the number of teeth, the corresponding RPM should decrease, and vice versa, for a meshed gear pair.