Charges on the metal painted table-tennis ball gain charges from the positively charged rod and becomes positively charged
Given:
f1 = 20 Hz
f2 = 20000 Hz
speed of sound at 20 degrees celcius = 343 m/s
Solution:
for f1 = 20 Hz,
Using the equation:
lambda = speed of sound / f1 = 343 / 20 = 17.15 m
For f2:
lambda = speed of sound / f2 = 343 / 20000 = 0.01775 m
Therefore the wavelength range of audible sound in air would be 17.15 m to 0.01775 m.
This question involves the concepts of dynamic pressure, volume flow rate, and flow speed.
It will take "5.1 hours" to fill the pool.
First, we will use the formula for the dynamic pressure to find out the flow speed of water:

where,
v = flow speed = ?
P = Dynamic Pressure = 55 psi
= 379212 Pa
= density of water = 1000 kg/m³
Therefore,

v = 27.54 m/s
Now, we will use the formula for volume flow rate of water coming from the hose to find out the time taken by the pool to be filled:

where,
t = time to fill the pool = ?
A = Area of the mouth of hose =
= 1.98 x 10⁻⁴ m²
V = Volume of the pool = (Area of pool)(depth of pool) = A(1.524 m)
V =
= 100.1 m³
Therefore,

<u>t = 18353.5 s = 305.9 min = 5.1 hours</u>
Learn more about dynamic pressure here:
brainly.com/question/13155610?referrer=searchResults
Answer: 0 J
Explanation: there’s no movement if it’s a wall