Hi there!
Initially, we have gravitational potential energy and kinetic energy. If we set the zero-line at H2 (12.0m), then the ball at the second building only has kinetic energy.
We also know there was work done on the ball by air resistance that decreased the ball's total energy.
Let's do a summation using the equations:

Our initial energy consists of both kinetic and potential energy (relative to the final height of the ball)

Our final energy, since we set the zero-line to be at H2, is just kinetic energy.

And:

The work done by air resistance is equal to the difference between the initial energy and the final energy of the soccer ball.
Therefore:

Solving for the work done by air resistance:


milligrams
Explanation:
The best unit to measure the mass of a grain of salt is the milligram.
This is about; a thousandth of a gram.
A grain of salt is a very small particle size that can still be visible with the eye.
It has a very low and small mass.
For substances like this, we use the milligram:
1000milligram = 1g
learn more:
Mass brainly.com/question/4736384
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Answer:
I would love to help, Could you put the question in English?
Explanation:
Stars having less mass collapses early than those with more mass. This can be explained by Einstein's equation E=mc².
According to this equation, mass of stars is converted into light due to thermonuclear reactions occuring in the core of star which acts as engine of the stars. This thermonuclear reactions keeps star alive. Thermonuclear reactions occurs slowly in massive stars hence massive stars live more than light stars.
Answer:
Final temperature, 
Explanation:
Given that,
Mass of silver ring, m = 4 g
Initial temperature, 
Heat released, Q = -18 J (as heat is released)
Specific heat capacity of silver, 
To find,
Final temperature
Solution,
The expression for the specific heat is given by :





So, the final temperature of silver is 21.85 degrees Celsius.