Gravitational forece can only attract whereas electomagatism can be attractive and repulsive
The magnet will be a useful tool to pick the paper clips because the magnet can attract the paper clips.
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Attraction of magnets</h3>
The like poles of magnets repel while unlike poles of magnets attracts. Magnets attracts irons or metallic materials.
The paper clips are mettalic or made of iron and hence the magnet will attract them.
There we can conclude that the magnet will be a useful tool to pick the paper clips because the magnet can attract the paper clips and will help to gather them together for easy picking.
Learn more about magnets here: brainly.com/question/14997726
Efficiency is calculated through dividing the actual mechanical advantage by the hypothetical mechanical advantage:
- the actual mechanical advantage is 9J because that's how much work the light bulb doing
- the hypo. mechanical advantage is 100J. Ideally, in a perfect world, the light bulb can convert 100J input into 100J output, but do to resistance and other factors it is not possible.

change the decimal to a percentage:

the light bulb had 9% efficiency