The dimensions of ice box cooler are 40 x 40 x 40 cm. Each wall is 4.5 cm thick and is made of plastic. If outside temperature is 24 0 C and icebox maintains interior temperature is 00 C . Thermal conductivity of plastic, k = 0.032 W/(K. m).. How much ice melts in 2 hours?
2. A 15 kg mass is attached to a vertical k-400 N/m spring, then pulled down and released. At some later time, the mass is 20 cm above equilibrium and moving up at 65 cm/s. If this state is t-0, then find a) the x(t) equation for the mass b) a sketch of x(t) and v(t) c) the time for the mass to reach equilibrium for the first time
I do not understand how they got K*= 40
From 40^3 = 40K^2
• 9 = 300E1/3K1/3, 9. = 12,000, w = $10, r = $400, E*,K* = ? In gptimum (MRTSI = " or comerc MPE ZE = 100 E **" MP =100 100 loo 400 > B = 4 E3401 • Since qo=12,000 > 112000 =300 3VEK - 40=3/40K2 = 40²=40k? K = 40 7 E*=1,600
A long steel bar of radius R=2.5 cm, k =50 W/(m °C), p= 7800 kg/m), and c = 0.5 kJ/(kg. . °C) is to be annealed by cooling slowly from 800.°C to 100.°C in an environment at temperature 50.°C. If the heat transfer coefficient between the environment and the surface of the bars is h = 45 W/(m .°C), determine the time required for the annealing process using lumped system analysis.
1.3 127 5.3 3.(10 pts) A cold storage room (10 m x 10 m x 10 m) is being maintained at 2 °C using a vapor compression refrigeration system that uses R-134a. The evaporator and condenser temperatures are -20 and 40°C, respectively. The walls and ceiling of the storage room is constructed of 15 cm thick concrete (thermal conductivity-1.37 WIm K]) and 4.3 cm thick insulation (thermal conductivity-0.04 W/[m K). The outside insulation surface temperature of the walls (or ceiling)...
3 (40 pts) An infinitely large plate of thickness 20 cm is insulated at the lower surface. Within the plate, heat is uniformly generated at a rate égen = 5 x 104 W/m2. The temperature of the air above the plate is known as Tair = (1 - sini z), where 1 = 3000 m and the origin of the coordinate system z starts from the upper surface of the plate. The physical properties of the plate: p = 7.9...
6. Solar radiation (525 W/m?) hits a concrete (p=1190 kg/m', k=0.5 W/m-K, Cp = 0.8 kJ/kg-K, a = 5 x 10-7 m/s) parking lot initially at 4°C. What will be the temperature (°C) 9.4 cm below the surface after 24 hours? Ignore convection and radiation from the concrete. (14 pts).
find the angle for polarizer 2
I (W/m/m) Intensity vs. position 800 Scenarios: 1 Correct Answer 600 400 200 0 x (cm) 0 5 10 15 20 25 30 40 incident light polarizer 1 polarizer 2 polarizer 3 I = 800.0 W/m^2 I = 400.0 W/m^2 I = ???? W/m^2 I = 149 W/m^2 polarizer 1 = 98 degrees polarizer 3 = 170 degrees The goal is to figure out the angle of polarizer 2. When you know what it...
A solid disk (M = 10 kg and R - 70 cm ) is rotating at 300 rpm initially. Then a smaller ring (m = 3.0 kg and r 40 cm ) is dropped concentrically onto the disk and they rotate together with a new angular velocity. (Hint: the rotational inertia of the small ring is mr, not ' mr !) 20. find the final angular velocity of the system in rpm. 21. find the change in rotational kinetic energy...
with steps please
04. For the system shown in Figure 4 where m-10 kg, k-100 kN/m, the governing equations has been derived as (1) Find the natural frequencies of the system; (2) Determine the associated mode shapes; and (3) Obtain the vibration response if the initial conditions are given as x,(0)-0,x,(0)-0.001 m, 2kE TIITTTUITTU Figure 4
04. For the system shown in Figure 4 where m-10 kg, k-100 kN/m, the governing equations has been derived as (1) Find the natural...