A horse is running at a speed of 12
meters per second. It takes the horse 3
seconds to come to a stop to drink at a
river. The average force needed to bring
the horse to a stop is 1,800 newtons.
What is the mass of the horse?

the dependant variable is spilled water

the independent is the heat

it's c (engineer's do their work with mechanical stuff not on any living being)

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.