In the first law, an object will not change its motion unless a force acts on it. So I think the answer is A. Only objects that are moving.
The length of the pendulum is 0.087 m. Option d is correct.
<h3>What is Simple harmonic motion?</h3>
Simple harmonic motion is periodic motion caused by a restoring force that is proportionate to the deviation from equilibrium.
Simple harmonic motion is periodic motion but many other conditions are dependent.
The time period of the pendulum is found as;

The length of the pendulum is 0.087 m
Hence, option d is correct.
To learn more about the simple harmonic motion refer to the link;
brainly.com/question/17315536
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The answer is modulation. In modulation a radio wave (also called the "carrier signal") is changed by the signal we want to send to the receiver, for example a song, or, in a wireless network, some data from a computer.