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.
Answer: 7750 J
Explanation:
Mechanical energy is potential energy added to kinetic energy.
5000 + 2750 J = 7750 J
the height of the building is H=36 m.
<h3>What is The Law of Gravity?</h3>
According to Newton's law of gravity, every particle of matter in the universe is attracted to every other particle with a force that varies directly as the product of their masses and inversely as their distance from one another.
Properties of Gravity -
- It is a universal attractive force. It is directly proportional to the product of the masses of the two bodies.
- It obey inverse square law.
- It is the weakest force known in nature.
Examples of Gravity -
- The force that holds the gases in the sun.
- The force that causes a ball you throw in the air to come down again.
- The force that causes a car to coast downhill even when you aren't stepping on the gas.
v₀=0 m/s
H₀=0 m
g=10 m/s²
t=7,2 s
H - ?

H = 0 +0 × 7.2 + 10(7.2)²/2
H = 36m
to learn more about Gravity go to - brainly.com/question/12528243
#SPJ4
I believe it’s density and temperature