Theoretically, if the objects have the same mass and are moving towards each other at a speed of

, after a perfectly elastic collision, the object A is supposed to move with the same velocity in the opposite direction.
It means that you consider the elements as a list organized by atomic number, the property is seen to repeat over and over as you move through that list.
Answer:
(a) Most reactive
Metal B
Metal D
Metal A
Least reactive
Metal C
(b) (i) Bubbles should form very slowly
(ii) No reaction takes place
Explanation:
(a) The given metals arranged in their order of reactivity are;
Most reactive
Metal B
Metal D
Metal A
Least reactive
Metal C
The other of reactivity is based on the nature of their reactivity of the metals in air
(b) (i) Based on the reactivity of the metals in air, whereby metal A reacts very slowly and an oxide is formed, we have that, based on the reactivity of the metal A, when mixed with dilute hydrochloric acid, bubbles should form very slowly
(ii) Similarly, given that metal C is unreactive, we have that when small pieces of metal C are added to dilute hydrochloric acid, no reaction takes place.
Answer:
Thin, aluminium and buried underground.
Explanation:
When it comes to electrification of a state or province, some characteristics of the wire to use must be considered. This would help to minimize and avoid power loss and wire burns.
i. The wire to use should be thin, and a quite number can be twisted one against the other so as to increase the surface area for heat dissipation.
ii. Aluminium wire is more preferable for this project. It has a high melting point, and reduces energy loss.
iii. Burying the wire underground through an insulator is the best choice, though expensive but would preserve the wire from external influence.