Two 11.5-mg balls are connected by a 28.9-cm-long insulating rod of negligible mass. One ball has a charge of +q and the other has a charge of −q. The system is placed in a 592 N/C uniform electric field. Initially the system is at rest and makes an angle α= 58.9° with respect to the field. It is then released, and when it is momentarily aligned with the electric field, its kinetic energy is 4.86 mJ. What is the magnitude of q?

Air is held within a frictionless piston-cylinder container, which is oriented vertically. the mass of the piston is 0.45 kg and the cross-sectional area is 0.0030 m2. initially (state 1) the pressure of the gas is sufficient to support the weight of the piston as well as the force exerted by the atmospheric pressure ( 101.32 kpa). the volume occupied by the air within the cylinder in state 1 is 1.00 liter. one end of a spring (with spring constant k = 1000 n/m) is attached to the top of the piston, while the other end of the spring is attached to a stage that can move vertically. initially the spring is undeflected and therefore exerts no force. then the stage is then moved quasistatically downward a distance of 10.0 cm, at which point the system reaches state 2. the piston-cylinder is not insulated; rather it remains in diathermal contact with the surroundings, which are at a constant temperature of 300 k. what is the change of pressure within the container?

Can anybody me with this? ? (picture included.)

What is the rate of 12 liters of water moving through a water hose in 4.0 minutes?