Answer:
Vr = 20 [km/h]
Explanation:
In order to solve this problem, we have to add the relative velocities. We must remember that velocity is a vector, therefore it has magnitude and direction. We will take the sea as the reference measurement level.
Let's take the direction of the ship as positive. Therefore the boy moves in the opposite direction (Negative) to the reference level (the sea).
![V_{r}=30-10\\V_{r}=20 [km/h]](https://tex.z-dn.net/?f=V_%7Br%7D%3D30-10%5C%5CV_%7Br%7D%3D20%20%5Bkm%2Fh%5D)
Answer:
I think D am not pretty show
The answer would be a radio wave
Answer:

Explanation:
Light rays coming from moon is blocked by the pencil
so as per figure we know that angle subtended by pencil and angle subtended by moon must be same
so we have

so we have

so we have

The molar mass of the sample is equal to the summation of the molar mass of the elementas multiplied by the abundance of the elements by mole. In this case, copper has an abundance of 93.69 percent while zinc has 6.31 percent. In this case, the average molecular weight is 63.67 g/mol