Easy question pls
which of the following substances is a fluid?
air
ice
sand
candles

The correct answer is A. Air

Explanation:

A fluid refers to a substance that flows or deforms due to external factors and other types of factors, in general terms, fluids include all liquids, gases, and substances in plasma state as in all of these molecules do not have a fixed arrangement but can move and therefore the substance can flow. On the other hand, solids are not fluids because due to the way molecules are organized and bonded in them they do not commonly deform or flow. This implies, the fluid substance is air, because this is a gas and thus a fluid, while others such as ice, sand, and candles are solids.

the answer is c.the valence of the atoms combine .

(newtons first law)

conservation of momentum law states :

momentum before collision = momentum after collision

momentum p (kg-m/s)= mass * velocity

say moving car=1 000 kg, velocity = 10 m/s then p = 1 000*10= 10 000 kg-m/s

say still car = 2 000 kg, velocity = 0 m/s then p = 2 000* 0 = 0 kg-m/s

total momentum prior to collision = 10 000 + 0 = 10 000 kg-m/s

momentum after collision = 10 000 kg-m/s

mass now = 1 000 kg+2 000 kg = 3 000 kg

10 000 = 3 000 kg* velocity m/s

10 000/3 000 = velocity

3.33 m/s = velocity after collision

an impulse is a force applied over time , momentum is exclusive of external forces and a perfect collision is implied