The correct answer to the question above is that the magician is seeking the wavelength of the standing wave. The part of a standing sound wave, which is its wavelength, the magician is seeking when playing a musical note of a specific pitch.
Answer:

Explanation:
given,
P (in kilo pascals), volume V (in liters), temperature T (in kelvins)
P V = 8.31 T
Rate of increase the temperature = 0.1 K/s
temperature = 285 K
Pressure = 18 kPa
increasing at the rate of 0.07 k Pa/s
Rate at which volume is changing = ?





I believe the correct answer from the choices listed above is the second option. With this information, he was able to conclude that the beam was negatively charged. His cathode ray<span> tube experiments led to a very important scientific discovery, the electron. Hope this answers the question.</span>
Explanation:
Draw free body diagrams for each mass.
There are 3 forces on the disk: weight force mg pulling down, normal force N pushing up, and tension force T pulling right.
There are 2 forces on the cylinder: tension force T pulling up and weight force 3mg pulling down.
Sum of forces on the disk in the centripetal direction:
∑F = ma
T = m v²/r
Sum of forces on the cylinder in the vertical direction:
∑F = ma
T − 3mg = 0
T = 3mg
Substituting:
3mg = m v²/r
3gr = v²
v = √(3gr)
Plug in values:
v = √(3 × 10 m/s² × 0.800 m)
v = √24 m/s
v ≈ 4.90 m/s