Solution :
From the given data,
For the spherical shell is 
where x is the radius of gyration and the acceleration of a rolling body on an inclined plane = a
Therefore,



= 0.6 x 9.81 x sin ( 29.7)




Δt = 1.411 s
The speed of the car is exactly 150/7200 km/sec, or 125/6 meters/sec.
In more familiar units, that speed is equivalent to ...
-- (20 and 5/6) meters/sec
-- 75 km/hour
ANS : 313℃
You need to use K in this.
To convert ℃ to Kelvin (K), add 273.15 to ℃.