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yan [13]
3 years ago
11

A mover hoists a 200 kg piano from the ground to a height of 10 m using a single pulley. What was the change in the pianos energ

y? a. 20j b. 200j c. 2000j d. 20000
Physics
2 answers:
RideAnS [48]3 years ago
7 0
P.E= Mass x gravity x height   (standard gravity = 10m/s approaximately)
     = 200x10x10= 20000j (D)
aivan3 [116]3 years ago
3 0

Answer: d. 20000 J

Explanation:

Potential energy is the energy possessed by an object by virtue of its position.

P.E=m\times g\times h

m= mass of object = 200 kg

g = acceleration due to gravity = 10ms^{-2}

h = height of an object

1. when h= 10 m

P.E=200\times 10ms^{-2}\times 10m=20000Joules

2. when h= 0 m

P.E=200\times 10ms^{-2}\times 0m=0Joules

Thus change in energy=(20000-0)Joules=20000Joules.

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mylen [45]

The distance covered by the acorn is 3.136 m.

<u>Explanation:</u>

The time taken for the acorn to hit the ground is 0.8 s. As it is a free fall, the acorn will be completely under the influence of gravity. So the acceleration will be acceleration due to gravity.

Then using the second law of equation,

s=ut+\frac{1}{2}gt^{2}

Since the initial velocity and time is zero, then the time taken to reach the ground is stated as 0.8 s, so

   s=0+\left(\frac{1}{2} \times 9.8 \times 0.8 \times 0.8\right)=\frac{6.272}{2}=3.136 \mathrm{m}

So the distance covered by the acorn is 3.136 m.

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When Jane is sliding down a slide, she is demonstrating translational motion. 
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What is the total force acting on the ball in the diagram? How would you describe its velocity?
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a whistle you use to call your hunting dog has a frequency of 21 khz, but your dog is ignoring it. you suspect the whistle may n
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To solve this problem we will apply the concepts related to the Doppler effect. According to this concept, it is understood as the increase or decrease of the frequency of a sound wave when the source that produces it and the person who captures it move away from each other or approach each other. Mathematically this can be described as

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