Complete Question
The complete question is shown on the first uploaded image
Answer:
The time taken is 
Explanation:
From the question we are told that
The value of 
The the interior temperature is 
The external temperature is 
The required interior temperature is 
The newton cooling law is

=> 
Now integrate both sides we have

Since c is a constant lnC = c will also give a constant so
=>
=>
substituting value


Hence


=> 

Answer:
K = 1800 kJ
Explanation:
Given that,
The speed of the object, v = 30 m/s
Mass of the object, m = 4000 kg
We need to find the kinetic energy of the object. The formula for the kinetic energy is given by :

So, the required kinetic energy is equal to 1800 kJ.
D: a force equal to the force
Answer:
4 m/s^2
Explanation:
The acceleration is defined as: Δv/Δt (the difference of the velocity over a time period in which happens that difference).
Remember that a difference is calculated by subtracting the initial value of a physical quantity from its final value.
In our case:
Δv = Vfinal - Vinitial = 36m/s - 0 m/s = 36m/s
Δt = 9s
a = Δv/Δt = 36m/s / 9s = 4m/s^2