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.
The scientist who discovered the two elements radium and polonium would be Marie Curie in 1898.
Hope this helps!
Answer:
The right approach is Option b (the force..................exert on you).
Explanation:
- Even before you fall on something like a soft object, users eventually slow to a halt. You are still giving away all the downward momentum, but progressively although with small powers, you are doing so.
- Although you can get injured by massive powers, this gradual displacement is a positive thing. And that is why you have a mattress you would like to settle on.
The other options given are not connected to the situation described. So, the solution here was the right one.
There is no definite end to earths atmosphere, but technically the border between the outer space and earth gets thinner as you move up from the earths surface. The Karman line is the closest definition there is which describes the end of the earth's atmosphere, it is 100 km above earth's sea level at approximately 1.56 % of total earth's radius. This describes the boundary between the outer space and the atmosphere.
