In which situation is maximum work considered to be done by a force? A. The angle between the force and displacement is 180°.
B. The angle between the force and displacement is 90°.
C. The angle between the force and displacement is 60°.
D. The angle between the force and displacement is 45°.
E. The angle between the force and displacement is 0°.

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.