Well an object in motion will stay in motion unless acted upon by the force, but what are the objects?
Putting glue on something, because once it is set in you cannot change it back.
Answer:
Sound waves travelling through the air: Sound waves travelling through air are just like longitudinal waves lacking compressions and rarefactions. The speed of sound waves in air is approximately 332 metres per second.
Light waves travelling through air: Light waves travel in air at a much faster rate than sound waves. Light waves can travel with a speed of 300 000 kilometres per second through air.
Sound waves traveling through metal: Sound waves travel about 17 times faster in metal as compared to air. The sound waves travel with an approximate speed of 5,960 meters per second in metals.
Light waves travelling through metal: The speed of light waves in a metal medium is usually at a net speed which is less than 3.00 x 108 m/s.
Light travels faster than sound waves because light waves are not pressure waves like the sound waves. They also do not require a medium as the sound waves.

(i) 1 mole of Ar =6.022×10^23
atoms of Ar
52 mol of Ar=52×6.022×10 ^23
atoms of Ar =3.131×10 ^25 atoms of Ar
(ii) Atomic mass of He = 4amu
Or
4amu is the mass of He atoms = 1
Therefore 52 amu is the mass of He atoms=0.25×52=13 atoms of He
(iii) Gram atomic mass of He = 4g
Or
4g of He contains =6.022×10 ^23
atoms
Therefore 52 g of He contains=
6.022×10 ^23/4×52 =7.83×10 ^24 atoms