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.
The attractive force between all matter in the universe is gravity.
Easy !
Take any musical instrument with strings ... a violin, a guitar, etc.
The length of the vibrating part of the strings doesn't change ...
it's the distance from the 'bridge' to the 'nut'.
Pluck any string. Then, slightly twist the tuning peg for that string,
and pluck the string again.
Twisting the peg only changed the string's tension; the length
couldn't change.
-- If you twisted the peg in the direction that made the string slightly
tighter, then your second pluck had a higher pitch than your first one.
-- If you twisted the peg in the direction that made the string slightly
looser, then your second pluck had a lower pitch than the first one.
Answer:
Z = R, i = V/Z, w = √1 / LC
Explanation:
In an RLC circuit the impedance of the circuit is
Z = √[R² + (
)²
Where
= wL
X_{L} = 1 / wC
They are the reactances of the inductor and the capacitor, in this case the current advances to the voltage in the first and is delayed from the voltage in the second, so when the two values give the same reactance the current goes in phase with the voltage and the impedance is minimal
Z = R
V= i Z
i = V/Z
Therefore the current is maximum, this occurs when
w = √1 / LC
Saying that this is the resonant frequency
