The amplitude of the wave is the 'full height of the wave.' Amplitude is measured in m (meters) and is measured over the change of a single period.
NaCl is a compound formed by a chemical reaction between Na (Sodium) and Cl (Chlorine). Sodium is an alkai metal in Group One of the Periodic Table, and it is very reactive. All alkai metals react violently with water and they are often found combined in nature because they are that reactive. Chlorine is a halogen in Group 17 of the Periodic Table and they are very reactive.
The answer to this question is a) sulfur
The weight is 45 N, because the three chains hold the sign, and each contributes 15 N.
Notice that the mass would be the weight/acceleration of gravity, m = 45/9.8 kg. But they ask the weight (force, so Newtons)
