T = 3.5 secs
Velocity (v) = g * t = 10 m/s^2 * 3.5 sec = 35 m/s
Answer:
Velocity, v = 0.239 m/s
Explanation:
Given that,
The distance between two consecutive nodes of a standing wave is 20.9 cm = 0.209 m
The hand generating the pulses moves up and down through a complete cycle 2.57 times every 4.47 s.
For a standing wave, the distance between two consecutive nodes is equal to half of the wavelength.

Frequency is number of cycles per unit time.

Now we can find the velocity of the wave.
Velocity = frequency × wavelength
v = 0.574 × 0.418
v = 0.239 m/s
So, the velocity of the wave is 0.239 m/s.
Given
Three 7 ohm resistor are in series.
The battery is V=10V
To find
The equivalent resistance
Explanation
When the resistance are in series then the resistance are added to find its equivalent.
Thus the equivalent resistance is:

Conclusion
The equivalent resistance is 21 ohm
True since coulomb's law states that There is electric force between like charges or opposite charges. The negative sign only shows the nature of the force.
<h3>What is the coulombs law ?</h3>
coulombs formula is given by

Now it states that if two charged particles are separated by the distance r and having same or opposite charge will attract or repel each other.
The intensity of the force depend upon the distance and the nature of the charge.
Hence coulomb's law states that There is electric force between like charges or opposite charges. The negative sign only shows the nature of the force.
To know more about coulomb's law follow
https://brainly.in/question/332179