Earth is like a bar magnet. what does this mean about its magnetic poles?

question 5 options:

a. there is only a magnetic north pole.

b. there are both magnetic north and south poles.

c. there is only a magnetic south pole.

d. there are two magnetic north poles.

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 ⇒

Need people build a dam to create a reservoir that supplies water a nearby city needs. describe two ways this action will likely affect the water cycle in the local environment. (5 points) worth 20 points

Which lists correctly orders nuclear reactions from most radioactive waste generated to least waste generated within a given period of time? o a. radioactive decay, nuclear fission, nuclear fusion o b. radioactive decay, nuclear fusion, nuclear fission o c. nuclear fusion, nuclear fission, radioactive decay o d. nuclear fission, nuclear fusion, radioactive decay