Wavelength = 20 m = 0.20 m
frequency = 3*10^8 / 0.20 = 1.5 * 10^9 Hertz
Answer:
The speed of sound can be gotten by simply finding the average of the results.
=0.756s
It is advisable for the students to repeat 5 times because it allows them to (a) estimate the variability of the results (how close to each other they are) and (b) to increase the accuracy of the estimate.
Answer:
72.04 dB.
Explanation:
The intensity level of 60dB corresponds to the sound intensity given by the equation
where
solving for we get:
Now, when 16 violins are playing the intensity becomes
which on the decibel scale gives
.
Thus, playing 16 violins together gives the intensity level of 72 dB.
P is disproportional to t, which means that if P increases with x factor, the t will decrease with the same x factor. If t increases then P decreases
(A) The total initial momentum of the system is
(1.30 kg) (27.0 m/s) + (23.0 kg) (0 m/s) = 35.1 kg•m/s
(B) Momentum is conserved, so that the total momentum of the system after the collision is
35.1 kg•m/s = (1.30 kg + 23.0 kg) <em>v</em>
where <em>v</em> is the speed of the combined blocks. Solving for <em>v</em> gives
<em>v</em> = (35.1 kg•m/s) / (24.3 kg) ≈ 1.44 m/s
(C) The kinetic energy of the system after the collision is
1/2 (1.30 kg + 23.0 kg) (1.44 m/s)² ≈ 25.4 J
and before the collision, it is
1/2 (1.30 kg) (27.0 m/s)² ≈ 474 J
so that the change in kinetic energy is
∆<em>K</em> = 25.4 J - 474 J ≈ -449 J