An electronic package with a surface area of $1 m^2$ placed in an orbiting space station is exposed to space. The electronics in this package dissipate all 1 kW of its power to the space through its exposed surface. The exposed surface has an emissivity of 1.0 and an absorptivity of 0.25. Determine the steady state exposed surface temperature of the electronic package (a) if the surface is exposed to a solar flux of $750 \mathrm{W} / \mathrm{m}^{2},$ and (b) if the surface is not exposed to the sun.

A solid plate, with a thickness of 15 cm and a thermal conductivity of $80 W/m \cdot K,$ is being cooled at the upper surface by air. The air temperature is $10^\circ C,$ while the temperatures at the upper and lower surfaces of the plate are 50 and $60^\circ C,$ respectively. Determine the convection heat transfer coefficient of air at the upper surface and discuss whether the value is reasonable or not for force convection of air.

How does the speaker say the prisoner should be affected by the movement of a leaf at forty days' distance?

A soldier jumps from a plane and opens his parachute when his velocity reaches the terminal velocity $V_T.$ The parachute slows him down to his landing velocity of $V_F.$ After the parachute is deployed, the air resistance is proportional to the velocity squared. The soldier, his parachute, and his gear have a total mass of m. Show that $k=m g / V_{F}^{2}$ and develop a relation for the soldier’s velocity after he opens the parachute at time t = 0.

The density of a floating body can be determined by tying weights to the body until both the body and the weights are completely submerged, and then weighing them separately in air. Consider a wood log that weighs 1540 N in air. If it takes 34 kg of lead $\left(\rho=11,300 \mathrm{kg} / \mathrm{m}^{3}\right)$ to completely sink the log and the lead in water, determine the average density of the log.

Choose a song on a CD or on your MP3 player. Listen to the song and describe the beats or rhythm using repeating numbers. For example, a song may have a rhythm that can be described by 1-2-3-1-2-3-$\ldots$.

A 60-gallon water heater is initially filled with water at $50^\circ F.$ Determine how much energy (in Btu) needs to be transferred to the water to raise its temperature to $120^\circ F.$ Evaluate the water properties at an average water temperature of $85^\circ F.$

Consider a 20-cm thick granite wall with a thermal conductivity of $2.79 W/m \cdot K.$ The temperature of the left surface is held constant at $50^\circ C,$ whereas the right face is exposed to a flow of $22^\circ C$ air with a convection heat transfer coefficient of $15 W/m^2 \cdot K.$ Neglecting heat transfer by radiation, find the right wall surface temperature and the heat flux through the wall.

Fully describe and graph the function $y=|2x-1|$.

Consider a person whose exposed surface area is $1.9 m^2,$ emissivity is 0.85, and surface temperature is $30^\circ C.$ Determine the rate of heat loss from that person by radiation in a large room whose walls are at a temperature of (a) 300 K and (b) 280 K.

Find the curvature $\kappa$ of the graph of each function at the indicated point. $4 x^{2}+9 y^{2}=36$ at (0,2)

For each vector function r=r(t), find the unit tangent vector T and the principal unit normal vector N at t. $\mathbf{r}(t)=\left(t^{2}+1\right) \mathbf{i}+(1-t) \mathbf{j} \quad t=1$

A piston/cylinder setup contains argon gas at 140 kPa and $10^{\circ} \mathrm{C}$, and the volume is 100 L. The gas is compressed in a polytropic process to 700 kPa and $280^{\circ} \mathrm{C}$. Calculate the polytropic exponent and the heat transfer during the process.

Evaluate. $10^{2}=$