Answer:
1. Electromagnetic waves travel in a vacuum whereas mechanical waves do not.
2. The ripples made in a pool of water after a stone is thrown in the middle are an example of mechanical wave. Examples of electromagnetic waves include light and radio signals.
3. Mechanical waves are caused by wave amplitude and not by frequency. Electromagnetic Waves are produced by vibration of the charged particles.
4. While an electromagnetic wave is called just a disturbance, a mechanical wave is considered a periodic disturbance.
Explanation:
When you heat a certain substance with a difference of temperature

the heat (energy) you must give to it is

where

is the specific heat of that substance (given in J/(g*Celsius))
In this case

Observation: the specific heat of a substance is given in J/(g*Celsius) or J/(g*Kelvin) because on the temperature scale a
difference of 1 degree Celsius = 1 degree Kelvin
Explanation:
formula: <u>Mass</u>
Density x volume
2a) m=10kg v=0.3m³
10÷0.3=33.3 kg/m
2b) m = 160 kg V=0.1m³
160÷0.1=1600 kg/m
2c) m = 220 kg V = 0.02m³
220÷0.02=11000 kg/m
A wooden post has a volume of 0.025m³ and a mass of 20kg. Calculate its density in kg/m.
density = volume ÷ mass
20÷ 0.025=800 kg/m
Challenge: A rectangular concrete slab is 0.80m long, 0.60 m wide and 0.04m thick. Calculate its volume in m³.
Formula : Length x width x height = Volume
0.80 x 0.60 x 0.04 = 0.0192m³
B) The mass of the concrete slab is 180 kg. Calculate its density in kg/m.
density = volume ÷ mass
180 ÷ 0.0192 = 9375 kg/m
Complete Question
The complete question is shown on the first uploaded image
Answer:
The workdone is 
Explanation:
From the question we are told that
The initial Volume is 
The final volume is 
The external pressure is
Generally the change in volume is

Substituting values we have


Generally workdone is mathematically represented as

W is negative because the working is done on the environment by the system which is indicated by volume increase
Substituting values


Now 
Therefore 

The buoyant force or upward buoyancy force