Potassium is in the most reactive group of elements, the alkali metals, but it's not the most reactive metal within the group. The alkali metals, Group 1A, are the most reactive metals because they have one valence or outer electron. They lose this electron very easily, forming ions with a charge of +1.
A boiling pot of water (the water travels in a current throughout the pot), a hot air balloon (hot air rises, making the balloon rise) , and cup of a steaming, hot liquid (hot air rises, creating steam) are all situations where convection occurs.
Since both hv same mass and elsstic collision, so their velocity will exchange. Bob A will stop and bob B will move with speed of A just before the collision.
Speed will be = squreroot ( 2*g*L)
L is length of pendulum
You can use Vf^2-Vi^2 = 2ax
Vf^2 - 0 = 2(9.81)(25)
Or you can use energy
mgh = 1/2mv^2
2gh =v^2
Same thing
Well when you eat you get energy and then you use it to ride up the hill sorry I don't know how it is classified