A device designed to shoot projectiles consists of a spring with spring constant kmewtons/meter that has been compressed Δx meters. A marble of mass m kilograms is loaded into the device. If the entire device is at an initial height h meters and is moving at an initial velocity v meters/second, which equation best represents the magnitude of the total initial energy E, in joules, of the system? E=12mgh+12kΔx2+12mv2

E=mgh+kΔx2+mv2

E=mgh+12kΔx2+12mv2

E=mgh+kΔx2+12mv2

The lid of a pressure cooker forms a nearly airtight seal. steam builds up pressure and increases temperature within the pressure cooker so that food cooks faster than it does in an ordinary pot. the system is defined as the pressure cooker and the water and steam within it. if 2.0 g of water is sealed in a pressure cooker and then vaporized by heating, and 5655 j must be added as heat to completely vaporize the water, what is the change in the system’s internal energy? answer in units of j.