Air at 20ºc with a convection heat transfer coefficient of 25 w/m2·k blows over a horizontal steel hot plate (k = 43 w/m·k). the surface area of the plate is 0.38 m2 with a thickness of 2 cm. the plate surface is maintained at a constant temperature of ts = 350°c, and the plate loses 300 w from its surface by radiation. calculate the inside plate temperature (ti). (round your answer up to 3 decimal places.)

Heat transfer due to convection = Heat transfer due to conduction

Heat transfer due to convection, Q = h_c*AdT
Where,
h_c =25 W/m^2K
A = 0.38 m^2
dT = 350 - 20 = 330 K
Substituting;
Q = 25*0.38*330 = 3135 W

Heat transfer through the hot steel plate, Q = (k/s)AdT
k = 43 W/m.k
s = 2 cm = 0.02 m
dT = ti - 350

Therefore,
3135 = (43/0.02)*0.38*(ti-3500
ti-350 = 3135/[(43/0.02)*0.38] = 3.837
ti = 3.837+350 = 353.837°

    5.5 n======    assuming that      we have      m = 0.145 kg    a = 38 m/s²therefore    5.51 n, but two significant figures.final answer: 5.5 n

Answer

the order for strong to weak forces such as

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

explanation

the fundamental forces are those forces that act between to objects or element to make interactions. there are four types of fundamental forces such as strong and weak nuclear forces (due to protons and electrons), electromagnetic force (due to the motion of electrons) and gravitational force (due to orbital movement of the planet). if these forces are arranged on the basis of their maximum strength then the order is

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force