C.
Explanation: ionic compounds are metals and nonmetals, refer to your periodic table
Answer:
The time it will take for the object to hit the ground will be 4.
Explanation:
You have:
h(t)=−16t²+v0*t+h0
Being v0 the initial velocity (54 ft/s) and h0 the initial height (40 ft) and replacing you get:
h(t)=−16t²+54*t+40
To know how long it will take for the object to touch the ground, the height h(t) must be zero. So:
0=−16t²+54*t+40
Being a quadratic function or parabola: f (x) = a*x² + b*x + c, the roots or zeros of the quadratic function are those values of x for which the expression is 0. Graphically, the roots correspond to the points where the parabola intersects the x axis. To calculate the roots the expression is used:

In this case you have that:
Replacing in the expression of the calculation of roots you get:
Expresion (A)
and
Expresion (B)
Solving the Expresion (A):

Solving the Expresion (B):

These results indicate the time it will take for the object to hit the ground can be -5/8 and 4. Since the time cannot be negative, then <u><em>the time it will take for the object to hit the ground will be 4.</em></u>
Given what we know, the light rays that you see on the surface of the mirror are at the same angle as the light rays that your friend sees.
<h3 /><h3>Why does this happen?</h3>
This has to do with the way in which a mirror affects the light that hits it. A mirror will reflect light, but will do so at the same angle that the light reaches it. This means that if the light reaches the mirror at a 40-degree angle, it will be reflected in the opposite direction at a 40-degree angle.
Therefore, we can confirm that the light rays that you see on the surface of the mirror are at the same angle as the light rays that your friend sees.
To learn more about light waves visit:
brainly.com/question/23342892?referrer=searchResults
The instantaneous velocity of the object is its speed and direction at that instant.