Answer:
39.2m/s
Explanation:
The potential energy the book has right before it falls is equal to the kinetic energy in falling.
PE = KE
mgh = (1/2)mv
2gh=v
v=(2)(9.81)(2)
v=39.24m/s
Answer:
<em>Infrared telescope and camera</em>
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Explanation:
An infrared telescope uses infrared light to detect celestial bodies. The infrared radiation is one of the known forms of electromagnetic radiation. Infrared radiation is given off by a body possessing some form of heat. All bodies above the absolute zero temperature in the universe radiates some form of heat, which can then be detected by an infrared telescope, and infrared radiation can be used to study or look into a system that is void of detectable visible light.
Stars are celestial bodies that are constantly radiating heat. In order to see a clearer picture of the these bodies, <em>Infrared images is better used, since they are able to penetrate the surrounding clouds of dust,</em> and have located many more stellar components than any other types of telescope, especially in dusty regions of star clusters like the Trapezium cluster.
Relative motion can best be defined as B<span> the motion of one object as it appears to another object.
An example is when you are in a car the car has the actual motion because it is the one moving but you are also moving because of relative motion.</span>
The ratio of the maximum photoelectron kinetic energy to the work function will be 3:1.
<h3 /><h3>What is the photoelectric effect?</h3>
When a medium receives electromagnetic radiation, electrostatically charged particles are emitted from or inside it.
The emission of ions from a steel plate when light falls on it is a common definition of the effect. The substance could be a solid, liquid, or gas; and the released particles could be protons or electrons.
A particular metal emits photoelectrons when exposed to light with energy three times its work function:

The ratio of the maximum photoelectron kinetic energy to the work function will be;

Hence, the ratio of the maximum photoelectron kinetic energy to the work function will be 3:1.
To learn more about the photoelectric effect refer to the link;
brainly.com/question/9260704
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