It is a surface force
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Both valves are closed during the power stroke.
While the fuel is burning in the cylinder, you want
all the force of the expanding gases to push the
piston down ... you don't want any of the gases
or their pressure escaping.
If either of the valves was open, even just a crack,
then part of the gases would go blooey out the valve,
and some pressure would be lost that's supposed to be
pushing the piston.
A switch
What are the answers choices
A prime example of how culture has contributed to human survival is the development of agriculture, which helps feed enormous numbers of people. Option A is correct.
<h3 /><h3>What is culture?</h3>
A population's collective ways of life are known as culture. The manner of life for an entire society has been said about culture. It encompasses manners, rituals, and artistic standards.
The invention of farming helps feed large populations of humans and is an example of how culture can help humans survive.
Hence option A is correct.
To learn more about the culture refer to:
brainly.com/question/12678729
#SPJ1
Explanation:
For each object, the initial potential energy is converted to rotational energy and translational energy:
PE = RE + KE
mgh = ½ Iω² + ½ mv²
For the marble (a solid sphere), I = ⅖ mr².
For the basketball (a hollow sphere), I = ⅔ mr².
For the manhole cover (a solid cylinder), I = ½ mr².
For the wedding ring (a hollow cylinder), I = mr².
If we say k is the coefficient in each case:
mgh = ½ (kmr²) ω² + ½ mv²
For rolling without slipping, ωr = v:
mgh = ½ kmv² + ½ mv²
gh = ½ kv² + ½ v²
2gh = (k + 1) v²
v² = 2gh / (k + 1)
The smaller the value of k, the higher the velocity. Therefore:
marble > manhole cover > basketball > wedding ring
