The phonograph was invented for people with hearing problems. Option D is correct.
<h3>
What is a Phonograph?</h3>
- It is a device that records sounds or music in the grooves of a plate and plays them.
- This was the first invention that can record and play music.
- It was invented by Thomas Alva Edison.
- This device helps people with hearing problems by allowing them to practice concentrating on a different sound.
Therefore, the phonograph was invented for people with hearing problems.
Learn more about Phonograph:
brainly.com/question/858851
Answer:
The time taken to rotate the sphere one time is, t = 22 s
Explanation:
Given data,
The mass of the sphere, m = 8200 kg
The radius of the sphere, r = 90 cm
= .9 m
The force applied by the girl, F = 75 N
The moment of inertia of the sphere is,
I = 2/5 mr²
= (2/5) 8200 x (.9)²
= 2657 kg·m²
The torque,
τ = I α
75 x 0.9 = 2657 x α
α = 0.0254 rad/s²
The angular displacement,
θ = ½αt²
2π = ½ x 0.0254 rad/s² x t²
t = 22 s
Hence, the time taken to rotate the sphere one time is, t = 22 s
Answer:
Explanation:
Here we know that for the given system of charge we have no loss of energy as there is no friction force on it
So we will have
now we know when particle will reach the closest distance then due to electrostatic repulsion the speed will become zero.
So we have
so distance moved by the particle is given as
I think it’s the second one: magnetic domains must come in pairs—one north and one south
Answer:
Explanation:
circumference of the tyre = 2πr = 2 x 3.14 x 0.26 = 1.6328m
76000km = 76000000m
no of revolutions required
= 76000000/1.6328 = 46546 revolutions.
