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guajiro [1.7K]
3 years ago
15

A machine has an efficiency of 70%. How much work dose the machine do when 20,000 J of work is done on it ?

Physics
1 answer:
Murrr4er [49]3 years ago
3 0

Answer: The machine does 14.000 J

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A frictionless pulley used to lift 8000N of concrete. What is the minimum effort required to raise the block
rusak2 [61]

Answer: 8000N

Explanation: since it is frictionless that means it has 100% efficiency therefore the mechanical advantage is 1 meaning the load equals to the effort

3 0
3 years ago
How do two sublevels of the same principal energy level differ from each other
Colt1911 [192]

Each energy sublevel corresponds to an orbital of a different shape.

Explanation:

Two sublevels of the same principal energy level differs from each other if the sublevels corrresponds to an orbital of a different shape.

  • The principal quantum number of an atom represents the main energy level in which the orbital is located or the distance of an orbital from the nucleus. It takes values of n = 1,2,3,4 et.c
  • The secondary quantum number gives the shape of the orbitals in subshells accommodating electrons.
  • The number of possible shapes is limited  by the principal quantum numbers.

Take for example, Carbon:

                      1s² 2s² 2p²

   The second energy level is 2 but with two different sublevels of s and p. They have different shapes. S is spherical and P is dumb-bell shaped .

Learn more:

Quantum number brainly.com/question/9288609

#learnwithBrainly

7 0
3 years ago
Which of the following is an example of the Doppler effect? A water bug on the surface of a pond is producing small ripples in t
noname [10]

Answer:

A police car with its siren on is driving towards you, and you perceive the pitch of the siren to increase.

Explanation:

In Physics, Doppler effect can be defined as the change in frequency of a wave with respect to an observer in motion and moving relative to the source of the wave.

Simply stated, Doppler effect is the change in wave frequency as a result of the relative motion existing between a wave source and its observer.

The term "Doppler effect" was named after an Austrian mathematician and physicist known as Christian Johann Doppler while studying the starlight in relation to the movement of stars.

<em>The phenomenon of Doppler effects is generally applicable to both sound and light. </em>

An example of the Doppler effect is a police car with its siren on is driving towards you, and you perceive the pitch of the siren to increase. This is so because when a sound object moves towards you, its sound waves frequency increases, thereby causing a higher pitch. However, if the sound object is moving away from the observer, it's sound waves frequency decreases and thus resulting in a lower pitch.

<em>Other fields were the Doppler effects are applied are; astronomy, flow management, vibration measurement, radars, satellite communications etc. </em>

3 0
3 years ago
A train has a length of 81.1 m and starts from rest with a constant acceleration at time t = 0 s. At this instant, a car just re
arlik [135]

Answer: a) vcar= 7 m/s ; b) a train= 0.65 m/s^2

Explanation: By using the kinematic equation for the car and the train we can determine the above values of the car velocity and the acceletarion of the train, respectively.

We have for the car

distance = v car* t, considering the length of train (81.1 m) travel by the car during the first 11.6 s

the v car =  distance/time= 81.1 m/11.6s= 7 m/s

In order to calculate the acceleration we have to use the kinematic equation for the train from the rest

distance train = (a* t^2)/2

distance train : distance travel by the car at constant speed

so distance train= (vcar*36.35)m=421 m

the a traiin= (2* 421 m)/(36s)^2=0.65 m/s^2

4 0
3 years ago
Can an object be in motion and not in motion at the same time? Explain.
kolezko [41]
It could rotate while not advancing distance
5 0
3 years ago
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