To solve this problem, we use the formula:
I100 / I1 = [P / 4π(100m)^2] / [P / 4π(1m)^2]
I100 / I1 = 1 / 100^2
I100 / I1 = 10^-4
Therefore the change in intensity from 1m to 100m in decibels is:
B100 – B1 = 10 log(10^-4) dB = -40 dB
So the intensity at 100m is calculated as:
B100 = B1 – 40 dB = 140 dB – 40 dB = 100 dB
Answer:
100 dB
Given Information:
Mass = m = 95 kg
Initial velocity = v₁ = 0 m/s
Final velocity = v₂ = 3 m/s
time = t = 15 seconds
Required Information:
magnitude of average force = ?
Answer:
magnitude of average force = 19 N
Explanation:
From the Newton's second law of motion
F = ma
From the kinematics equations,
v₂ = v₁ + at
at = v₂ - v₁
a = (v₂ - v₁)/t
a = (3 - 0)/15
a = 0.2 m/s²
F = 95*0.2
F = 19 N
Therefore, the magnitude of the average force required to bring the sled to rest is 19 N.
Answer:
31.25 year .
Explanation:
The thickness of layer must change so the destructive interference may be converted into constructive interference . This can happen if thickness is reduced by λ /4 , so that path difference changes by 2 x λ /4 = λ /2 .
This will convert destructive to constructive interference.
change in thickness required = λ /4
= 525 / 4 nm
= 131.25 nm .
year required to wear off
= 131.25 / rate of decay
= 131.25 / 4.2
= 31.25 year .
Answer:
Final velocity of the object(v) = 114 m/s
Explanation:
Given:
Initial velocity (u) = 14 m/s
Accelerates (a) = 5 m/s²
Time taken = 20 seconds
Find:
Final velocity of the object(v) = ?
Computation:
According to 1st law of motion.
⇒ v = u +at
⇒ v = 14 + (5)(20)
⇒ v = 14 + 100
⇒ v = 114 m/s
Final velocity of the object(v) = 114 m/s
