I would say mass, and weight.
Answer:
(a) The ratio of the pressure amplitude of the waves is 43.21
(b) The ratio of the intensities of the waves is 0.000535
Explanation:
Given;
density of gas,
= 2.27 kg/m³
density of liquid,
= 972 kg/m³
speed of sound in gas,
= 376 m/s
speed of sound in liquid,
= 1640 m/s
The of the sound wave is given by;

Where;
is the pressure amplitude

(b) when the pressure amplitudes are equal, the ratio of the intensities is given as;

Principle: Pythagorean theorem
Given:
Let a = boat velocity = 25 miles per hour
b = river velocity = 10 miles per hour
Required: c = actual velocity
Solution:
c^2 = a^2 + b^2
c^2 = (25)^2 + (10)^2
c^2 = 725
(c^2)^0.5 = (725)^0.5
c = 26.93 miles per hour
<em>ANSWER: Actual boat velocity is 26.93 miles per hour</em>
Answer:
The inventors claim is not real
a) No the the freezer cannot operate in such conditions
Explanation:
From the question we are told that
The power input is 
The rate of heat transfer 
The temperature of the freezer content is 
The ambient temperature is 
Generally the coefficient of performance of a refrigerator at idea conditions is mathematically represented as

substituting values


Generally the coefficient of performance of a refrigerator at real conditions is mathematically represented as

substituting values


Now given that the COP of an ideal refrigerator is less that that of a real refrigerator then the claims of the inventor is rejected
This is because the there are loss in the real refrigerator cycle that are suppose to reduce the COP compared to an ideal refrigerator cycle where there no loss that will reduce the COP