So we want to know how can we detect infrared rays without an instrument. Infrared rays or heat, are a part of electromagnetic spectrum. We have specialized nerve cells in our skin called thermoreceptors that can detect differences in temperature that are produced by infrared part of EM spectrum.
The correct answer is:
<span>C) The actual frequency of the siren does not change despite appearances.
In fact, Bob will observe an increase in the apparent frequency as the emergency vehicle approaches him, while Jill will observe a decrease in the apparent frequency as the emergency vehicle moves away from him, because of the Doppler effect (the relative velocity between the observer and the source of the sound is changing), but this effect involves the apparent frequency, while the real frequency of the siren will remain the same.</span>
Answer:
<h3>30m</h3>
Explanation:
Velocity is the change of rate of displacement with respect to time.
velocity = displacement/time
Given
initial velocity = 15 m/s.
time taken =2 secs
Required
Displacement of the object
From the formula;
Displacement = Velocity * time
Displacement = 15 * 2
Displacement = 30m
<em>Hence the displacement of the object is 30m</em>
There is a ner force of 15 N allowing Levi and Clara to mobe the box.
