1-) Uma carga elétrica Q é colocada em um ponto do espaço vazio. Este sistema elétrico tem energia potencial elétrica? Explique.
2-) Sejam duas cargas elétricas de valores iguais a 2x10(elevado a -6) C e 4x10(elevado a -4) C separadas por uma distância igual a 3m. Quanto vale a energia potencial elétrica deste sistema?

What is an aquifer for science class

An astronaut in space cannot use a scale or balance to weigh objects because there is no gravity. but she does have devices to measure distance and time accurately. she knows her own mass is 77.4 kg , but she is unsure of the mass of a large gas canister in the airless rocket. when this canister is approaching her at 3.50 m/s , she pushes against it, which slows it down to 1.30 m/s (but does not reverse it) and gives her a speed of 2.60 m/s . what is the mass of the canister?

Panel bc in fig. p2.76 is semi-circular, with the 3 meter radius and horizontal straight edge through point b. compute (a) the hydrostatic force of the water on the panel, (b) its center of pressure, and (c) the moment of this force about point b. assume atmospheric pressure on the dry side of the panel