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finlep [7]
3 years ago
7

A crane lifts a piano weighing 9,000 N to the roof of a 7-story building. The height of each floor (story) of the building is 3

m. How much work is done by the crane?
Physics
1 answer:
Mandarinka [93]3 years ago
8 0

Answer:

W = 189 kJ

Explanation:

If kinetic energy does not change, the work done increases the potential energy

W = mgh =9000(7(3)) = 189 kJ

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The bending of light as it passes into a transparent material of different optical intensity is known as A. conversion. B. aberr
stiks02 [169]

Answer:

<em>D. refraction</em>

Explanation:

Refraction: Refraction is change in direction of light rays. Refraction occurs whenever light rays travels from a transparent medium to another transparent medium of different density. The abrupt change in direction at the surface of the surface of the two media is referred to as <em>refraction</em><em>.</em>

<em>Refraction occurs when light travels from air to glass or from air to liquid.</em>

<em>Laws Of Refraction:</em>

(i) The incident ray, the refracted ray and the normal, all at the point of incident lies in the same plane.

(ii) The ratio of the sine of the angle of incident to the sine of the angle of refraction is a constant for a given pair of media.

<em>Thus the right option is D. refraction</em>

6 0
3 years ago
Earth’s atmosphere is in hydrostatic equilibrium. What this means is that the pressure at any point in the atmosphere must be hi
Misha Larkins [42]

Answer: The pressure that one experiences on the Mount Everest will be different from the one, in a classroom. It is because pressure and height are inversely proportional to each other. This means that as we move up, the height keeps on increasing but the pressure will keep on decreasing. This is the case that will be observed when one stands on the Mount Everest as the pressure is comparatively much lower there.

It is because as we move up, the amount of air molecules keeps on decreasing but all of the air molecules are concentrated on the lower part of the atmosphere or on the earth's surface.

Thus a person in a low altitude inside a classroom will experience high pressure and a person standing on the Mount Everest will experience low pressure.

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3 years ago
Un bloque de 25 n se encuentra suspendido por un hilo al techo vitamina la tensión que aparece en el hilo
SVETLANKA909090 [29]

Answer:

T = 25 N

Explanation:

The question says that "A 25 n block is suspended by a wire from the ceiling vitamin the tension that appears in the wire ?"

Weight of the block, W = 25 N

Weight of a body acts in downward direction and tension acts in upward direction. It would mean that,

Tension = weight of the block

T = mg

T = 25 N

Hence, the tension in the wire is 25 N.

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3 years ago
If a baseball travels a distance of 4 meters in 5 seconds, what is its average speed
Alisiya [41]

Answer:

speed=d/t.

s=4/5=0.8m/s.

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Eleven truly inspiring adjectives !
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