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
Answer:

Explanation:
Gauge pressure at the bottom of the cylinder depends on the height of water in the cylinder
So here we can say that

now when liquid is filled to height "h" in base area "A" then gauge pressure of the liquid at the bottom is given as

now we put the whole liquid into another cylinder with twice radius of the first cylinder
So area becomes 4 times
now by volume conservation we can say that if area is increased by 4 times then height of liquid will decrease by 4 times
so we have

so gauge pressure is given as

Answer:
(a) 3107.98 J
(b) 14530.6 J
Explanation:
mass, m = 3.56 kg
angular speed, ω = 179 rad/s
Moment of inertia of solid cylinder, I = 1/2 mr^2
where, m is the mass and r be the radius of the cylinder.
(a) radius, r = 0.330 m
I = 0.5 x 3.56 x 0.330 x 0.330 = 0.194 kgm^2
The formula for the rotational kinetic energy is given by

K = 0.5 x 0.194 x 179 x 179 = 3107.98 J
(b) radius, r = 0.714 m
I = 0.5 x 3.56 x 0.714 x 0.714 = 0.907 kgm^2
The formula for the rotational kinetic energy is given by

K = 0.5 x 0.907 x 179 x 179 = 14530.6 J
Answer:
The correct answer is the spring constant (k)
Explanation:
- Elastic potential energy: Epe = ½ * k * Δx²
k = spring constant
Δx = displacement
- Gravitational ptential energy: Ep = m*g*h
g = (acceleration due to gravity)
m = mass
h = relative height of an object to some reference point
Answer: 0.42watts
Explanation:
Energy of the battery = 500 J
Time = 1200 seconds
Power of the instrument = ?
Recall that power is the rate of energy expended in doing work. Thus, power is energy expended divided by time taken.
i.e Power = (energy/time)
Power = 500J/1200 seconds
Power = 0.416 watts (Round to the nearest hundredth which is 0.42 watts)
Thus, the power of the instrument is 0.42watts