Atividade 1) A presença do campo magnético terrestre proporciona alguns efeitos interessantes. Dentre eles estão as auroras polares. Faça uma pesquisa e explique como esse fenômeno ocorre. Atividade 2 Utilizando a simulação mostrada na figura abaixo, aproxime o ímã da bússola em várias posições ao longo do plano. a) O que representam as pequenas agulhas ao redor do ímã? b) O que acontece com a agulha da bússola quando o ímã é movimentado ao seu redor? c) Marque a seleção "Mostrar medidor de campo". Movimente o medidor de campo O que você observa em relação ao campo magnético⃗ , quando o medidor de campo se aproxima do imã? c) Marque a caixa de seleção "planeta Terra". Como são mostradas as polaridades do ímã? Por que aparece dessa forma?

During physical science, ms. greene challenged her students to produce an energy transformation. james and jill wrapped a 4-inch nail with a coil of fifty turns of wire. they connected one end of the coil to one terminal of a knife switch. they connected the other terminal of the knife switch to the battery. finally, they connected the end of the coil to the other terminal of the battery. james held the tip of a 1-inch nail near the flat end of the 4-inch nail. jill closed the knife switch quickly and then opened it. the 1-inch nail was pulled toward the 4-inch nail. what is the best explanation of why the nail moved? a) electrical energy was converted to mechanical energy in the 1-inch nail. b) the 4-inch nail became an electromagnet and the magnetic force attracted the 1-inch nail. c) the electric current in the 4-inch nail was converted to mechanical energy in the 1-inch nail. d) the 4-inch nail had a positive charge and the 1-inch nail had a negative charge. opposites attracted.

When does your body conduct current more readily?

Suppose water is leaking from a tank through a circular hole of area ah at its bottom. when water leaks through a hole, friction and contraction of the stream near the hole reduce the volume of water leaving the tank per second to cah 2gh , where c (0 < c < 1) is an empirical constant. a tank in the form of a right-circular cone standing on end, vertex down, is leaking water through a circular hole in its bottom. (assume the removed apex of the cone is of negligible height and volume.) (a) suppose the tank is 20 feet high and has radius 8 feet and the circular hole has radius 2 inches. the differential equation governing the height h in feet of water leaking from a tank after t seconds is dh dt = − 5 6h3/2 . if the height of the water is initially 8 feet, how long will it take the tank to empty? (round your answer to two decimal places.)