When a bat uses echolocation to determine the distance to an insect, it sends out a sound wave and waits to see how long the sound takes to echo back. Suppose now that a bat hears its echo 0.06 LaTeX: ss after it emitted the sound. If the speed of sound is 344.9 LaTeX: \frac{m}{s}m s, how far away is the insect in meters?

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.