9. Un automóvil parte del reposo y se acelera uniformemente a 10 m/s2 para pasar dos semáforos consecutivos que se encuentran separados 200 m. Si el vehículo tarda 4s en pasar los dos semáforos, determine la distancia a la que se encuentra el primer semáforo del punto de partida.

two charges are fixed in place on the x-axis as shown. the charge at x = 0 is negative and has magnitude q = 2 μcoulombs (1 μcoulomb = 10-6 coulombs). the charge at x = d, (d = +12 cm), is positive and has magnitude q = 4 μcoulombs. find a point x = xo along the x-axis at which the electric field is zero.

an electric circuit