please help with the newton's law?

Question

what does this law mean?
the rate at which a body cools is proportional to the temperature difference between the object and its surroundings.

Answer 1

....in other words - the cooler the surroundings, the faster the 'hot' object will cool down.

Answer 2

this is newton's law of cooling... it means that the larger the difference there is in the temperature of an object and the surrounding, the faster the rate of cooling will be or the slower if the difference is smaller until the equilibrium temperature is reached (or the temperature of the surrounding). it may also be applied for heating if the temperature of the object is lower than the surrounding... i think...

Answer 3

dQ/dt ~ mdT is math talk for "the rate at which a body cools is proportional to the temperature difference between the object and its surroundings" dQ is the change in heat, if dQ < 0, then heat is being lost...the object with mass m and with the heat Q is cooling. dt is the change in time; the elapsed time it took for the heat to change dQ. Thus dQ/dt is the "rate" of change in the heat.

Similarly dT is the change in temperature. It is the "temperature difference." Finally ~ in math talk means proportional to. So dQ/dt ~ mdT, in a nice succinct package, means the rate of change (cooling or heating) of heat is proportional to the temperature differential.

Any time we say "proportional" there has to be a constant of proportionality to make the ~ turn into a =, and equals sign. So to change dQ/dt ~ mdT into an equation, with an =, we can add a constant, say, C. And, we give it a cool (pun intended) name, like heat conductivity. Then we have dQ/dt = CmdT.

Once you know C and mass for the material with the heat Q and you measure the two temperatures, you can find out the cooling rate (if the material T > t outside) or heating (if T < t). Just about all materials texts have a table of C values for a wide range of materials.

Note that m, the object's mass, plays a role in the rate of heat transfer. This results because, at a given temperature, a more massive body has more heat to transfer. It's something like a big dam has more water behind it than a small dam. More heat in the bigger mass exerts more "pressure" for a given temperature differential.

Answer 4

Well, it means that if a body is 100 degrees, and the air is 90 degrees, its going to cool down at one rate.

But if the air is 50 degrees, the body is going to cool down faster.

To figure out the "proportional" part, you need to use absolute temperatures, not Fahrenheit or Celsius.

Answer 5

This is not one of Newtons Laws.

Answer 6

I think it might be that 'everything that goes up, must come down'?