I'll mark you brainliest :)
Which of the following is not an example of a pure element?
Ar
Copper wire
CO{2}
O{2}

 copper wire

Explanation:

Copper wire is not an example of a pure element because although it's made by pure elements, it's not one itself.

O2

Explanation:

Co2 is a pure mixture while O2 is a substance, but oxygen by itself is an element. Copper in any form, wire, bar, tube is still an element. Shape does not affect an element being an element.

Ar is a pure element.

(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