Bajo la acción del viento una puerta gira un ángulo de 90° en 5 s. Calcular su velocidad angular y la velocidad lineal de los puntos del borde si el ancho de la puerta es de 50 cm. R. 0,314 rad/s, 0,157 m/s.

Students in an introductory physics lab are performing an experiment with a parallel-plate capacitor made of two circular aluminum plates, each 11 cm in diameter, separated by 1.0 cm. how much charge can be added to each of the plates before a spark jumps between the two plates? for such flat electrodes, assume that value of 3×106n/c of the field causes a spark.