Answer: The earth is a noisy place. Seismometers, which measure ground movements to detect earthquakes, volcanic eruptions, and manmade explosives, are constantly recording smaller vibrations caused by ocean waves, rushing rivers, and industrial activity.

Explanation:

6 0

3 years ago

Which two energy sources can help a star maintain its internal thermal pressure? which two energy sources can help a star mainta

Lapatulllka [165]

Nuclear fusion and gravitational contraction

<span>constituent of star is hydrogen(including isotope) or helium. nuclear fission is almost impossible. D(deuterium; isotope of hydrogen) and T(tritium; also isotope of hydrogen) reacts and helium is formed. During this reaction, severe energy is generated. Heavier elements are formed and pulls each other. Gathered elements forms core of star. Gravity of the core prevents the gas to run away.</span>

8 0

4 years ago

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A 0.75-kg ball falls vertically downward from a height of 55.0 m and rebounds upward. if the ball reaches a height of 30.0 m and

Nikitich [7]

Impuls I is given by:
$I = \delta mv = |F|t$
where $\delta mv$ is the change in momentum, $|F|$ is the average force and t is the time.

Solve the equation for the force F:
$|F| = \frac{\delta mv}{t} = \frac{m(v_f - v_i)}{t}$

Energy should be conserved, so the velocities will be:
$\frac{1}{2}mv^2 = mgh \\ v = \sqrt{2gh}$

Combining both equations:
$|F| = \frac{m( \sqrt{2g(h_f + h_i)} )}{t}$
where $h_f = 30m, h_i = 55m, m = 0.75kg, t = 0.0025s$

4 0

4 years ago