A wood log (k = 0.17 W/m · K and a = 1.28 × 10-7 m²/s) is 7.5 cm in diameter and is initially at a uniform temperature of 15°C. It is exposed to hot gases at 500°C in a fireplace with a heat transfer coefficient of 13.6 W/m2 · K on the surface. If the ignition temperature of the wood is 420°C, determine how long it will be before the log ignites.

I am attaching both questions for 4 and 5 with the question in the image. thank you. NOTE : So the last person answered this question WITHOUT refencing the answer for whether question 4 or 5 answeres were given, so i am asking for question 5(or the answer for the question that was NOT solved because it was not referenced.) These were the following answers given to me from the last person on bartleby who answered my question without referencing whether it was the answer for question 4 or 5.  1 pass 2 fail 3 fail 4 pass

What is the degree of freedom of the two questions

Question 16 Here is a way we can estimate the distance from the earth to the moon. When the moon is seen at its zenith at a point A on the earth, it is observed to be at the horizon from point B. Points A and B are 6152 miles apart and the radius of the earth is 3960 miles. 20 Earth 0= B a) Calculate the angle in radians. (Round your answer to 5 decimal places.) d= ? v Moon Details b) Estimate the distance from point A to the moon using your angle from part a). (Round your answer to the nearest thousand.) ?