Question

1. emma and luis hold up a strand of hair and point two identical hair dryers at it. when they turn both dryers to the same setting, the hair begins to bend toward the right. emma claims she can balance the forces on the hair without turning either dryer off. which of the following would most likely produce the change in motion necessary to support emmas claim? a point hair dryer 2 downward so it blows air onto the floor instead of the hair. b move hair dryer 2 so that it is the same distance from the hair as hair dryer 1. c change the setting of hair dryer 2 so that it is blowing less air than hair dryer 1. d move hair dryer 2 so that both dryers are blowing on the left side of the hair.

Explanation:

Step1: Analyze force - balance concept

To balance forces on the hair, the net force acting on it should be zero. Currently, the hair is bending to the right, meaning there is a net - force to the right.

Step2: Evaluate option A

If we point Hair Dryer 2 downward, it will no longer exert a horizontal force on the hair, but this doesn't balance the force from Hair Dryer 1 acting on the hair horizontally.

Step3: Evaluate option B

Moving Hair Dryer 2 to the same distance from the hair as Hair Dryer 1 doesn't necessarily balance the forces as the direction and magnitude of the air - flow (force) are still not adjusted to counteract the force from Hair Dryer 1.

Step4: Evaluate option C

Changing the setting of Hair Dryer 2 so that it blows less air than Hair Dryer 1 will not balance the forces. It will still result in a net - force in the direction of the stronger air - flow (from Hair Dryer 1).

Step5: Evaluate option D

If both dryers are blowing on the left side of the hair, the forces exerted by the two dryers on the hair can be adjusted to be equal and opposite (in the horizontal direction), which can balance the forces on the hair.

Answer:

D. Move Hair Dryer 2 so that both dryers are blowing on the left side of the hair.