You would know a decomposition reaction occurred if the reactants separated. For example from AB → A+B.
Now if you look at your options only 1 works out for that equation. Letter A.
From the compound K2CO3 it split up to K2O +CO2
It cannot be letter B because synthesis/combination occurred. The same goes for letter C. Letter D, single displacement occurred.
Again, the answer is A.
The answer is 30 ... same as the Atomic number.
The period of a simple pendulum is given by:
where L is the length of the pendulum and
is the gravitational acceleration. As we can see, the period of a simple pendulum depends only on its length.
It's not that the laws of motion are any different on Earth than in space. But Earth's gravitational field has such an overwhelming force it masks their precise effects. And gravity is integral to all sorts of phenomena that we take for granted.
