Question

In a room where the temperature is 30° C, a body cools from 61° C to 59° C in 4 minutes. Calculate the time taken by the body to cool from 51° C to 49° C.

Answer 1

We apply Newton's law of cooling.    dQ/dt = m s dT/dt = k (T - T₀)
     T₀ = room temperature,  T₁ = initial temperature,  t = time duration
     T₂ = final temperature,  m = mass, s = specific heat, 

So    Ln [(T₂ - T₀)/(T₁ - T₀)] = (k /ms)* t

For the first cooling from T₁=61C to T₂=59C,  t = 240 sec, T₀=30C
        Ln [29/31]  = (k/m*s)* 240

For the second cooling from T₁= 51C  to T₂=49C, t = ?, T₀=30C
          Ln [19/21] = (k/m*s) * t

 So    t = 240 * Ln (19/21)  /  Ln(29/31)   sec
           = 360.17 sec
           = 6 min 0.17 sec

Answer 2

Answer:

hi hotty tthe answer is your asss