Use the worked example above to you solve this problem. find the energy transferred in 1 h by conduction through a concrete wall 1.6 m high, 4.00 m long, and 0.20 m thick if one side of the wall is held at 20°c and the other side is at 5°c.

The energy transferred is 2.93 MJ.

Explanation:

Given that,

Time = 1 h = 3600 s

Area

Width

Temperature

For concrete wall,

The thermal conductivity

k = 1.7 W/mK

Using Fourier's law

Where, A = area

= width

= change in temperature

k = thermal conductivity

Put the value into the formula

The energy transferred in 1 hour

Hence, The energy transferred is 2.93 MJ.

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.