At the time that I'll call ' Q ', the height of the stone that was
dropped from the tower is
H = 50 - (1/2 G Q²) ,
and the height of the stone that was tossed straight up
from the ground is
H = 20Q - (1/2 G Q²) .
The stones meet when them's heights are equal,
so that's the time when
<span>50 - (1/2 G Q²) = 20Q - (1/2 G Q²) .
This is looking like it's going to be easy.
Add </span><span>(1/2 G Q²) to each side.
Then it says
50 = 20Q
Divide each side by 20: 2.5 = Q .
And there we are. The stones pass each other
2.5 seconds
after they are simultaneously launched.
</span>
Answer:
Explanation:
All the rest of the information is extraneous. The only 2 things you have to know are
d = 20 km
t = 8 minutes = 8/60 hours = 0.13333333
So the speed is s = d/t
s = 20/0.1333333 = 150 km/hour
Note: you have not specified what units the speed is. I suppose you could answer 20/8 = 2.5 km/min
Ionic bond: it is also called "electrovalent bond". It is "a type of chemical bond that can often form between metal and non-metal ions through electrostatic attraction";
Covalent bond is a form of chemical bonding, "characterized by the sharing of pairs of electrons between atoms, or between atoms and other covalent bonds";
Metallic bond: "the chemical bond, which is characteristic of metals, in which mobile valence electrons are shared among atoms in a usually stable crystalline".
