Question

part 9 - mechanical comprehension instructions
when the belt moves in the direction shown, which pulleys turn
clockwise?
a only 1
b only 2
c only 3
d both 1 and 2 only
e all of them
if c is your answer, click the next button. otherwise, select another answer.

Explanation:

Step1: Analyze Pulley 1

When the belt moves as shown, Pulley 1 rotates counter - clockwise. The direction of the belt movement at the point of contact with Pulley 1 (from the top) causes it to rotate against the clockwise direction.

Step2: Analyze Pulley 2

For Pulley 2, the belt movement at its contact points (from the bottom and side) also results in a counter - clockwise rotation.

Step3: Analyze Pulley 3

For Pulley 3, the belt movement at its contact points (from the side and bottom) causes it to rotate clockwise. The belt is moving in a way that “pushes” the pulley in the clockwise direction at the contact regions.

Answer:

C. only 3