Bennett Mechanical Comprehension Practice Test 2026 – The Complete All-in-One Guide to Exam Success!

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Question: 1 / 400

What is the rotation velocity and direction of wheel C if wheel A makes 30 rot/min and RA = 3RB and RC = 2RB?

15 rot/min

60 rot/min

45 rot/min

To determine the rotation velocity and direction of wheel C, we first need to establish the relationship between the wheels based on their radii and the given rotation speed of wheel A.

It is provided that wheel A rotates at 30 rotations per minute (rot/min) and has a radius (RA) that is 3 times the radius of wheel B (RB). Therefore, we can express this relationship as RA = 3RB. Wheel C has a radius (RC) that is 2 times the radius of wheel B (RB), or RC = 2RB.

When comparing the rotation speeds of connected wheels, the principle of conservation of energy must be upheld. The linear speeds of the edges of connected wheels must be equal. The linear speed (v) of the edge of a wheel is calculated using the formula:

v = rot/min × radius

For wheel A:

v_A = 30 rot/min × RA

For wheel B, since RA = 3RB:

v_B = (30 rot/min × 3RB) = 90RB

Since wheel B connects to wheel C, we use the relationship of their radii to find the rotation speed of wheel C. The linear speed must also equal the linear speed of wheel

Bennett Mechanical Comprehension Practice Test 2026 – The Complete All-in-One Guide to Exam Success!

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