Explanation:
Since, it is mentioned the there occurs no change in the temperature. This also means that there will occur no change in thermal energy of the system.
Hence, 
= 0. And, as = 0 then there will be no work involved. This means that total energy added to the house will return to the outside air as heat.
Therefore,
Q = -(19000 J + 2000 J)
= -21000 J
or, |Q| = 21000 J
Thus, we can conclude that the magnitude of the energy transfer between the house and the outside air is 21000 J.
C is correct. Only a closed circuit can carry current, opening a switch disconnects the circuit and stops current from flowing. Remember, all current flows in loops, if you can't make a loop out of it, current can't flow, and opening a switch, assuming no other paths for current exist, will completely stop the current.
Answer:
When iron rusts - in the presence of moisture and oxygen - iron-oxide is formed. Iron oxide is nothing but a compound of iron and oxygen. There is an increase in the mass of the iron equal to the mass of oxygen that has gone into forming the rust.
<em>hope it helps:)</em>
Answer:
Explanation:
There will be reaction force by each vertical post on horizontal plank . Let it be R₁ and R₂ . R₁ is reaction force by the post nearer to woman
Taking torque of all forces about the end far away from the woman
Torque by reaction force = R₁ x 5.5
= 5.5 R₁ upwards
Torque by weight of woman in opposite direction , downwards
= - 804 x ( 5.5 - 1.55 )
= - 3175.8
Torque by weight of the plank in opposite direction , downwards .
= - 27 x 5.5 / 2
= - 74.25
Torque by R₂ will be zero as it passes through the point about which torque is being taken .
Total torque
= 5.5 R₁ - - 3175.8 - - 74.25 = 0 ( For equilibrium )
5.5 R₁ = 3250
R₁ = 590.9 N .
