Answer:
-4×-2y=14 (1)
-10×+7y=-25 (2)
multiplying eq 1 by 7 and eq 2 by 2 and add eq. 1 and 2
-28×-14y=98
-20×+14y=-50
___________
-28×=48
×=48/-28
×=-12/7
now
-4×-2y=14
-4*-12/7-2y=14
48/7-2y=14
-2y=14-48/7
-2y=(98-48)/7
-2y=50/7
y=-50/14
y=-25/7
Answer:
According to the law of conservation of energy, energy cannot be created or destroyed, although it can be changed from one form to another. KE + PE = constant. A simple example involves a stationary car at the top of a hill. As the car coasts down the hill, it moves faster and so it’s kinetic energy increases and it’s potential energy decreases. On the way back up the hill, the car converts kinetic energy to potential energy. In the absence of friction, the car should end up at the same height as it started.
This law had to be combined with the law of conservation of mass when it was determined that mass can be inter-converted with energy.
One can also imagine the energy transformation in a pendulum. When the ball is at the top of its swing, all of the pendulum’s energy is potential energy. When the ball is at the bottom of its swing, all of the pendulum’s energy is kinetic energy. The total energy of the ball stays the same but is continuously exchanged between kinetic and potential forms
Answer:
stars will emit more light due to their Luminosity, so they look very bright.
Explanation:
Luminous refers to..,
- The total amount of energy radiated by a star or other celestial object per second.
- Therefore it is the power output of a star.
Most of the really bright stars in our sky are not that very close to us yet they look bright because of the Luminosity of the star.
These stars are intrinsically so luminous.
A star's power output across all wavelengths is called its bolometric luminosity.
A star with large luminosity will have more measure of radiated electromagnetic power meaning.
so it will emit more light than a low luminosity star.
Hence,
those stars can easily be seen even across great distance.
learn more about Luminosity of the star here:
<u>brainly.com/question/13912549</u>
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the rate of work done or doing work is usually measured by the power of a machine .
