Question

4 noah and ava release a feather in front of two identical box fans. when they turn both fans on to the same setting, the feather begins to drift to the right.
noah claims he can balance the forces on the feather without turning off the fans. which of the following would most likely produce the change in motion necessary to support noah’s claim?
a point fan 2 downward so that it is blowing air onto the floor.
b change the setting of fan 2 so that it blows less air than fan 1.
c move fan 2 so that it further away from the feather than fan 1.
d move fan 2 so that it is blowing air directly onto the opposite side of the feather from fan 1.

Explanation:

To balance the forces on the feather (which is drifting right, meaning net force is right), we need an equal and opposite force. If Fan 2 blows air on the opposite side of the feather from Fan 1, the force from Fan 2 will oppose Fan 1's force. Let's analyze options:

• Option A: Blowing downward doesn't oppose the horizontal (rightward) force from Fan 1, so it won't balance horizontal motion.
• Option B: Making Fan 2 blow less air would still result in a net rightward force (since Fan 1's force is stronger), not balance.
• Option C: Moving Fan 2 farther away would decrease its force, but it still acts in the same direction (assuming same orientation), so net force remains right.
• Option D: Blowing on the opposite side means Fan 2's force is leftward, opposing Fan 1's rightward force. If their magnitudes are equal (since fans are identical and settings can be adjusted or same), the forces will balance, stopping the drift.

Answer:

D. Move Fan 2 so that it is blowing air directly onto the opposite side of the feather from Fan 1.