Answer:
6.40 m/s
Explanation:
Here we have to consider the conservation of energy
Potential energy of a object = Kinetic Energy
Mgh = 1/2 M (v)2
V = root 2gh
V = root 2*10*20.5
V = 6.40 m/s
The energy that substance contain is. B.heat
First reason is safety, of course.
Second reason, the hot object radiates heat in the form of convection current which will heat the air around it.
This current can cause instabilities in measurements especially when using sensitive digital scales.
The answer would definitely be Conservation . Conservation is saving something .