Grades 5-6 Video Solutions 2023-2023_1-2

Video Transcription

Question 20. The gear marked A is turned clockwise as shown. Which two boxes will move upwards?  Taking a look at our gears, knowing that the gear marked A is going to be turned clockwise,  main thing to recognize about gears is that the connected gear will move the opposite direction.  So the gear below will move counterclockwise. Here we see a gear that is connected by a belt,  so this gear will go the same direction, also counterclockwise. Keeping our focus on the left  side, we have another large gear, and since this one's connected to the smaller gear that's going  counterclockwise, this big gear will also go clockwise. Now the pulley that it is attached to  is crossed over with the belt. That means it will be turning counterclockwise, which will bring the  box number two up. Going to the right side of the gears, we see another large gear. It will turn  clockwise, and the small gear will turn counterclockwise, meaning the pulley turns clockwise, bringing box number three up. So this will give us our answer, which will be B.

Video Summary

When gear A is turned clockwise, the gear directly connected to it moves counterclockwise due to their connection. The belt-connected gear also moves counterclockwise, causing the larger gear on the left side to move clockwise. This clockwise motion turns a pulley counterclockwise because of a crossed belt, raising box number two. On the right side, the large gear turns clockwise, causing the small gear to move counterclockwise, and the connected pulley clockwise, lifting box number three. Therefore, boxes two and three move upwards, making the correct answer B.

Keywords

gear mechanism

clockwise motion

pulley system

box lifting

crossed belt