Answer:
The frequency of the phonograph record is 0.2 Hz
Explanation:
The frequency of an object moving in uniform circular motion is the number of completed cycles the object makes in a specified time period
The given parameters of the phonograph record are;
The radius of the record = 0.15 m
The number of times the phonograph record rotates, n = 18 times
The time it takes the phonograph record to rotate the 18 times, t = 90 seconds
The frequency of the phonograph record, f = (The number of times the phonograph record rotates) ÷ (The time it takes the phonograph record to rotate the 18 times)
∴ The frequency of the phonograph record, f = n/t = 18/(90 s) = 0.2 Hz
The frequency of the phonograph record = 0.2 Hz.
<h2>
Resultant is 235.54 pounds at an angle 44.16° to X axis.</h2>
Explanation:
Forces are 100 pound and 150 pound and angles with x axis are 20°and 60°.
That is force 1 is 100 pound with x axis at 20°
F₁ = 100 cos 20 i + 100 sin 20 j
F₁ = 93.97 i + 34.20 j
That is force 2 is 150 pound with x axis at 60°
F₂ = 150 cos 60 i + 150 sin 60 j
F₂ = 75 i + 129.90 j
F₁ + F₂ = 93.97 i + 34.20 j + 75 i + 129.90 j
F₁ + F₂ = 168.97 i + 164.10 j

Resultant is 235.54 pounds at an angle 44.16° to X axis.
Answer:
Density of 127 I = 
Also, 
Explanation:
Given, the radius of a nucleus is given as
.
where,
- A is the mass number of the nucleus.
The density of the nucleus is defined as the mass of the nucleus M per unit volume V.

For the nucleus 127 I,
Mass, M = 
Mass number, A = 127.
Therefore, the density of the 127 I nucleus is given by

On comparing with the density of the solid iodine,

Answer:
I think its the Blue wave, im not sure so dont take my word for it.
Explanation:
Let volume of empty boat be = 100% = 1V
and mass of boat be M
In water 10%, 0.1V of the volume is submerged.
Mass, m of 1200kg increases the submerging from 10%, 0.1V to 70%, 0.7V
M leads to 0.1V boat submerging
boat submerging.
M + 1200kg leads to 0.7V boat submerging.
This is 60%, 0.6 V increase
By comparison
(M+1200kg) * 0.1V = 0.7V * M
0.1M + 120kg = 0.7M
120kg = 0.7M - 0.1M
120kg = 0.6M
M = (120/0.6)kg
M = 200kg.
The mass of the boat is 200kg.