Answer:
The question does not state how the answer is to be entered. I would use 10% because that is most common.
Explanation:
You are using 300 J of energy to get 30 J of light energy. The fact that you can account for the left over energy is not relevant.
Efficiency = Work Out / Work In
Efficiency = 30 J / 300 J = 0.1
If you need this as a %, you can multiply by 100
Efficiency = 0.1 * 100 = 10%
12.
Because why calculating displacement you only take two points in time, in this situation being the initial position and the final position. The distance between these two points is 12 kilometers.
I mean i guess its the metric system?
Answer:
The height (in m) above the floor of the top and bottom of the smallest mirror in which he can see both the top of his head and his feet is;
1.835 m and 0.88 m.
Explanation:
Here we have the total height of the man as
1.76 + 0.15 = 1.91 m
The mirror is positioned such that the person can see both the top of his head and his feet
We have the eyes are 0.15 m below the top of the head, therefore by the law of reflection, the incident and reflected angle must be equal.
Hence, the light from the top of his head and then reflected to his eyes forms a isosceles triangle, with the base being the distance of the eye to the top of his head and the top of the triangle is on the mirror.
The height of the mirror is then
1.91 - 0.15/2 = 1.835 m
Similarly, the distance from the eye to the feet is 1.76, therefore, the base of the mirror is positioned at 1.76/2 or 0.88 m above the ground.
Answer:
The mass of the rule is 56.41 g
Explanation:
Given;
mass of the object suspended at zero mark, m₁ = 200 g
pivot of the uniform meter rule = 22 cm
Total length of meter rule = 100 cm
0 22cm 100cm
-------------------------Δ------------------------------------
↓ ↓
200g m₂
Apply principle of moment
(200 g)(22 cm - 0) = m₂(100 cm - 22 cm)
(200 g)(22 cm) = m₂(78 cm)
m₂ = (200 g)(22 cm) / (78 cm)
m₂ = 56.41 g
Therefore, the mass of the rule is 56.41 g
