Una barra conductora de L = 0,9 m se mueve sin fricción sobre dos rieles conductores horizontales, Unos extremos de los rieles se conectan a una batería de 15 V y un interruptor. La barra se mueve en una región donde existe un campo magnético uniforme
B = −1,5 ˆz T. La barra tiene una masa de 0,5 kg y una resistencia de 8 Ω.
a) Encuentre la aceleración de la barra, en t = 0 s, justo cuando se cierra el interruptor.
b) Encuentre la aceleración de la barra cuando se mueve hacia la derecha con rapidez 2 m/s.

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.

Find the dimensions and area of the largest rectangle that can be inscribed in the upper half of the ellipse. (give your answers in terms of a and b. enter the dimensions as a comma-separated list.)

If element x has 99 protons how many electrons does it have