A250 g object is hung from a vertical spring, stretching it 18cm below its original equilibrium position. how much work is done by gravity? by the spring?

Which types of electromagnetic waves have higher frequencies than the waves that make up ultraviolet light? check all that apply. radio waves infrared light microwaves gamma rays visible light x-rays

Could someone me find the answer to this problem.

Consider a 1000 w iron whose base plate is made of 0.5 cm thick aluminum alloy 2024-t6 (ρ = 2770 kg/m3 and cp = 875 j/kg°c). the base plate has a surface area of 0.03 m2. initially, the iron is in thermal equilibrium with the ambient air at 22°c. assuming 90% of the heat generated in the resistance wires is transferred to the plate, determine the minimum time needed for the plate temperature to reach 200°c.