ANOTHER RUNNING DOG
Explanation:
In the given question it is to find a suitable reference point to describe the motion of dog. Here I could suggest that it is better to compare the dog with another running dog to create the relative speed difference to get a reliable motion variation.
Because the motion of dog is in the linear with respect to the another dog and to the acceleration produced by the dog in the required interval is easy to calculate with respect to another dog which is already in motion.
Hence, I suggest that Motion of dog can be analysed better by analyse the motion variation of dog with another dog running.
(a)
The velocity of the meteorite just before hitting the ground is:

The loss of energy of the meteorite corresponds to the kinetic energy the meteorite had just before hitting the ground, so:

(b) 1 megaton of tnt is equal to

To find to how many megatons the meteorite energy loss

corresponds, we can set the following proportion

And so we find

So, 0.162 megatons.
(c) 1 Hiroshima bomb is equivalent to 13 kilotons (13 kT). The impact of the meteorite had an energy of

. So, to find to how many hiroshima bombs it corresponds, we can set the following proportion:

And so we find

So, the energy released by the impact of the meteorite corresponds to the energy of 12.46 hiroshima bombs.
D. is the correct answer.
Absolute, Atmospheric, Differential, and Gauge Pressure