Find the number of molecules of water having volume 1 litre and its density :1g\cc mass​

diagram is missing, but i will try to explain your doubt.

answer:

amplitude is the maximum displacement or distance moved on a point of a vibrating body or wave measured from its equilibrium position.it is equal to half the length of vibration path.

a.) travels faster in solids because the particles are closer together.

air is a gas water is a liquid

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.

pythagoras' theorem

square root (-5^2+9^2)

square root (25+81)

square root (106)

angle is tan^-1(9/5)

neg x, pos y