Answer:
Sound intensity levels are quoted in decibels (dB) much more often than sound intensities in watts per meter squared. Decibels are the unit of choice in the scientific literature as well as in the popular media. The reasons for this choice of units are related to how we perceive sounds. How our ears perceive sound can be more accurately described by the logarithm of the intensity rather than directly to the intensity. The sound intensity level β in decibels of a sound having an intensity I in watts per meter squared is defined to be β(dB)=10log10(II0)β(dB)=10log10(II0), where I0 = 10−12 W/m2 is a reference intensity. In particular, I0 is the lowest or threshold intensity of sound a person with normal hearing can perceive at a frequency of 1000 Hz. Sound intensity level is not the same as intensity. Because β is defined in terms of a ratio, it is a unitless quantity telling you the level of the sound relative to a fixed standard (10−12 W/m2, in this case). The units of decibels (dB) are used to indicate this ratio is multiplied by 10 in its definition. The bel, upon which the decibel is based, is named for Alexander Graham Bell, the inventor of the telephone.
Table 1. Sound Intensity Levels and IntensitiesSound intensity level β (dB)Intensity I(W/m2)Example/effect01 × 10–12Threshold of hearing at 1000 Hz101 × 10–11Rustle of leaves201 × 10–10Whisper at 1 m distance301 × 10–9Quiet home401 × 10–8Average home501 × 10–7Average office, soft music601 × 10–6Normal conversation701 × 10–5Noisy office, busy traffic801 × 10–4Loud radio, classroom lecture901 × 10–3Inside a heavy truck; damage from prolonged exposure[1]1001 × 10–2Noisy factory, siren at 30 m; damage from 8 h per day exposure1101 × 10–1Damage from 30 min per day exposure1201Loud rock concert, pneumatic chipper at 2 m; threshold of pain1401 × 102Jet airplane at 30 m; severe pain, damage in seconds1601 × 104Bursting of eardrums
The momentum of the red cart before the collision is 0.2 kgm/s and the blue cart is 0.
The momentum of the red cart after the collision is 0.05 kgm/s and the blue cart is 0.15 kgm/s.
The change in momentum of the system of the carts is 0.
<h3>
Initial momentum of the carts before collision</h3>
The momentum of the carts before the collision is calculated as follows;
P(red) = 0.5 kg x 0.4 m/s = 0.2 kgm/s
P(blue) = 1.5 x 0 = 0
<h3>Momentum of the carts after collision</h3>
The momentum of the carts after the collision is calculated as follows;
P(red) = 0.5 x 0.1 = 0.05 kgm/s
P(blue) = 1.5 0.1 = 0.15 kgm/s
<h3>Change in momentum of the carts</h3>
ΔP = (0.05 + 0.15) - (0.2)
ΔP = 0
Learn more about momentum here: brainly.com/question/7538238
Answer:
38.6 J
Explanation:
c = molar heat capacity of silver = 25.35 J/(mol °C)
m = given mass of silver = 9.00 g
M = Molar mass of silver = 108 g
n = Number of moles of silver
Number of moles of silver are given as
n = 0.0833
Q = Energy needed to raise the temperature
ΔT = Change in temperature = 18.3 °C
Energy needed to raise the temperature is given as
Q = n c ΔT
Q = (0.0833) (25.35) (18.3)
Q = 38.6 J
Answer:
Parabola
Explanation:
The motion of a projectile consists of two independent motions:
- A uniform motion along the horizontal (x) direction, with constant velocity 
. In fact, there are no forces acting along this direction (if we neglect air resistance), so the acceleration is zero and the velocity is constant
- An uniformly accelerated motion along the vertical (y) direction, with constant acceleration 
downward (acceleration due to gravity). This acceleration is due to the force of gravity that pulls the projectile downward.
The composition of these two motions gives a parabolic trajectory. In fact, the equations of the motion along the two directions are:
(1)
(2)
Solving for t in eq.(1),
and substituting into (2)
which is the equation of a parabola.
