Explanation:
It is known that relation between torque and angular acceleration is as follows.
and, I = 
So, 
= 4 
So, 
= 1
as
= 
Hence, 
Thus, we can conclude that the new rotation is 
times that of the first rotation rate.
About 80% of the earth's volume is made of mantle.
<span>The </span>mantle<span> is a layer inside a </span>terrestrial planet<span> and some other </span>rocky planetary bodies<span>. For a mantle to form, the planetary body must be large enough to have undergone the process of </span>planetary differentiation<span> by </span>density<span>. The mantle lies between the </span>core<span> below and the </span>crust<span> above. The terrestrial planets (</span>Earth<span>, </span>Venus<span>, </span>Mars<span> and </span>Mercury<span>), the </span>Moon<span>, two of </span>Jupiter<span>'s </span>moons<span> (</span>Io<span> and </span>Europa<span>) and the </span>asteroid Vesta<span> each have a mantle made of </span>silicate<span> rock.</span><span>Interpretation of spacecraft data suggests that at least two other moons of Jupiter (</span>Ganymede<span> and </span>Callisto<span>), as well as </span>Titan<span> and </span>Triton<span> each have a mantle made of </span>ice<span> or other </span>solid volatile<span> substances </span>up of Mantle
Hope this helped.
