<span>Density can be calculated and found by dividing the sample's mass by its volume. D=m/v</span>
Answer:
r₂ = 0.2 m
Explanation:
given,
distance = 20 m
sound of average whisper = 30 dB
distance moved closer = ?
new frequency = 80 dB
using formula
I₀ = 10⁻¹² W/m²
now,
to hear the whisper sound = 80 dB
we know intensity of sound is inversely proportional to square of distances
r₂ = 0.2 m
Mostly gravity voloume and sometimes what it is made of
Answer:
<em>a. True</em>
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Explanation:
I'll assume the question is about magnetic latches and locks.
Magnetic door locks use an electromagnetic force to stop doors from opening, so they are ideal for security. There are two main types of electric locking devices. Locking devices can either be a fail-secure locking device that remains locked when power is lost, or a fail-safe locking device that is unlocked when de-energized. An electromagnetic lock creates a magnetic field when energized or powered up, this causes an electromagnet and armature plate to become attracted to each other strongly enough to keep a door from opening.
