Answer:
a) the three longest wavelengths = 4.8m, 2.4m, 1.6m
b) what is the frequency of the third-longest wavelength = 75Hz
Explanation:
The steps and appropriate formula and substitution is as shown in the attached file.
Answer:
c. natural force or pull toward the earth
Explanation:
Gravity of the earth is the force of attraction that it naturally possesses to attract any mass.
An apple falls on the earth due to this force of gravity.
The force of gravity near to the surface of the earth is given as:
where:
m= mass of the body
g= acceleration due to gravity
The variation of the gravitational force with height is given as:

where:

where
R = radius of the earth 
Answer:
Electrical Energy
Explanation:
An electric generator is a device that changes kinetic energy to electrical energy through electromagnetic induction. Electromagnetic induction is the process of generating electric current with a magnetic field. ... Because the coil is rotating in a magnetic field, electric current is generated in the wire.
Answer: thermal energy
Explanation: Thermal energy is the conversion of kinetic energy