Rachel has three different samples of rare Earth metals. The first sample has a mass of 5.5. 10-grams, the second has a mass of 1.4 grams, and the third has a mass of 4.4 . 10-2 grams. Ignoring significant figures, what is the sum of these three masses?
11.3.10-59
1.449510-09
1.44959
11.39

Explain the consequences of this addiction to the brain tissue

The frequency of vibrations of a vibrating violin string is given by f = 1 2l t ρ where l is the length of the string, t is its tension, and ρ is its linear density.† (a) find the rate of change of the frequency with respect to the following. (i) the length (when t and ρ are constant) (ii) the tension (when l and ρ are constant) (iii) the linear density (when l and t are constant) (b) the pitch of a note (how high or low the note sounds) is determined by the frequency f. (the higher the frequency, the higher the pitch.) use the signs of the derivatives in part (a) to determine what happens to the pitch of a note for the following. (i) when the effective length of a string is decreased by placing a finger on the string so a shorter portion of the string vibrates df dl 0 and l is ⇒ f is ⇒ (ii) when the tension is increased by turning a tuning peg df dt 0 and t is ⇒ f is ⇒ (iii) when the linear density is increased by switching to another string df dρ 0 and ρ is ⇒ f is ⇒

The heliocentric and the geocentric models of the solar system included these central principles