Both balls hit the ground at the same time.
We've known this fact for about 500 years (since Galileo),
and we've known WHY for about 300 years (since Newton).
Answer: (A) 1.5 m
Explanation:
This situation is due to Refraction, a phenomenon in which a wave (the light in this case) bends or changes its direction when passing through a medium with an index of refraction different from the other medium.
In this context, the index of refraction is a number that describes how fast light propagates through a medium or material.
In addition, we have the following equation that states a relationship between the apparent depth
and the actual depth
:
(1)
Where:
is the air's index of refraction
water's index of refraction.
is the actual depth of water
Now. when
is smaller than
the apparent depth is smaller than the actual depth. And, when
is greater than
the apparent depth is greater than the actual depth.
Let's prove it:
(2)
Finally we find the apparent depth of water, which is smaller than the actual depth:
![{d}^{*}=1.5 m](https://tex.z-dn.net/?f=%7Bd%7D%5E%7B%2A%7D%3D1.5%20m)
Answer:
20.6 cm
Explanation:
charge per cm = 0.14 μC
number of electrons (e) = ![1.8 x 10^{13}](https://tex.z-dn.net/?f=1.8%20x%2010%5E%7B13%7D)
to get the length of tape pulled we can apply the formula below
length of tape = ![\frac{magnitude of charge of the electrons}{charge per cm}](https://tex.z-dn.net/?f=%5Cfrac%7Bmagnitude%20of%20charge%20of%20the%20electrons%7D%7Bcharge%20per%20cm%7D)
therefore we need to find the magnitude of the charge of the electrons
- 1 electron =
C
now that we have the magnitude of the charge, we can find the length of the tape
- length of the tape =
= 20.6 cm
A high pitch always corresponds to a high frequency wave
Answer: The correct explanation is 2.
Explanation: The warm air is less dense (it expands) and thus it is lighter than the cold air so it will rise up to the floor. Therefore, when you place the heater on the floor it will warm the cold air which would then rise and be replaced by more cold air which would again get warm and rise and so on until the room is heated. This means that the correct explanation is 2.
On the other hand, if you put the heater at the ceiling, it will warm the cold air near the ceiling which would stay up there (it is lighter than the cold air under it). This means that the only way for the heat to spread from this ceiling level warm air to the lower levels is via conduction which is slow.