Answer:
C) 10 cm
Explanation:
We shall first calculate the focal length of the mirror.
object distance u = 20 cm ( negative )
Image distance v = 12 cm ( negative )
using mirror formula
1/ v + 1 /u = 1/ f
-1/12 - 1/ 20 =1/ f
f =- 7.5 cm
In the second case
u = - 30 cm
f = - 7.5 cm
i / v + 1 / u = 1 / f
1 / v - 1/30 = - 1/ 7.5
v = -10 cm
Answer is C that is 10 cm
A CLOSED SYSTEM. In a closed system in which energy moves freely in and out, but no matter enters or leaves.
1. I think is letter b.
2. I thinks it's letter c.
Answer:

Explanation:
<u>Average Density
</u>
The density of an object of mass m and volume V is

If we know the density and the volume occupied by the object, the mass can be computed as

The tank can hold 20 L of gasoline when full. Converting to cubic meters

That's the volume of the gasoline it contains. Knowing the density of the gasoline, we get the mass of gasoline.

To know the total mass of both, we add the 2.5 kg of the tank

The volume of the tank is computed solving for V


The total volume is

The average density is

