If the specific gravity of copper is 8.91, it weighs:
a. 55.6 lb/ft^3
b. 238.8 lb/ft^3
c. 23.88 lb/ft^3
d. 556 lb/ft^3

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.

How do the forces acting on a boat compare to the force acting on a plane ?

If you held a stone over the mouth of a well and then let it go , what would happen to the stone? explain your answer.