Homework #$10$C

PHYS $2141$

A copper wire, $40\mathrm{.}000$ cm in length $L_0,$ is heated causing its length to expand by $0\mathrm{.}300$ cm $[L.$ Calculate the temperature change $T,\{C\}$ needed to cause this change in length. Use formula $L=**L_0**T$ and the Table on page $3$ of Chapter #$12$ notes.

A $25\mathrm{.}000-cm$ length $L_0$ aluminum wire at $20\mathrm{.}0C$ is heated to $125\mathrm{.}0C$ causing it to expand. Calculate the wire's new length in centimeters. Report your answer to three decimal places. This problem is like Example #$5($pages $4$ and $5)$ in Chapter #$12$ notes.

$3$ and $4)$

A door's dimensions are $2\mathrm{.}02$ m by $0\mathrm{.}600$ m $.$ Looking at the door's side, you see the following layers: oak wood $($thickness: $0\mathrm{.}318$ cm $),$ fiberboard $($thickness: $3\mathrm{.}17$ cm $),$ and oak wood $($thickness: $0\mathrm{.}318$ cm $)$ again. The outside temperature is $10\mathrm{.}0C$ while the inside temperature is $22\mathrm{.}0C.$ This problem is like Examples #$3$ and #$4($pages $4$ and $5)$ in Chapter #$13$ notes. You will find a table of $k-$values on page $2$ of the notes.

Calculate the Heat Flow Rate $H,\{\frac{J}{s}\}$ through the door. Report as a positive value.

Calculate the amount of Heat $Q,\{J\}$ lost through the door in $10\mathrm{.}0$ minutes. Report your answer in joules.