Question

Unit 5 & 6: Non-Contact Forces Test
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Question
A student is conducting an experiment on the magnetic forces between a magnet and a paperclip. The magnet is placed on a scale in which the weight reads 2.00 ounces. A paperclip is suspended above the magnet so that the edge of the paperclip is just touching the magnet. Because the paperclip is exerting an upward force on the magnet, the scale now reads 1.63 ounces.

Image related to the assessment question
Now the student begins a new experiment in which they place a stronger magnet on the scale. This magnet also weighs 2.00 ounces. Predict what will happen when the same paperclip is suspended above the magnet.

Responses

The scale will read exactly 2.00 ounces because the paperclip will not have an effect on the strong magnet.
The scale will read exactly 2.00 ounces because the paperclip will not have an effect on the strong magnet.

The scale will read less than 1.63 ounces because the paperclip will exert an even greater upward force on the magnet.
The scale will read less than 1.63 ounces because the paperclip will exert an even greater upward force on the magnet.

The scale will read more than 1.63 ounces but less than 2.00 ounces because the stronger magnet will pull the paperclip down with even more force.
The scale will read more than 1.63 ounces but less than 2.00 ounces because the stronger magnet will pull the paperclip down with even more force.

The scale will read exactly 1.63 ounces because the paperclip that is used in this experiment is the same paperclip that was used in the first experiment.

Answer 1

The scale will read less than 1.63 ounces because the paperclip will exert an even greater upward force on the magnet.

Explanation: A stronger magnet produces a larger magnetic attraction, so it pulls the paperclip more. By Newton’s 3rd law the paperclip then pulls up on the magnet with a larger force, reducing the net downward force on the scale, so the reading drops below 1.63 oz.