A solution that is 0.024 M in Na+ can be prepared by adding how many grams of Na2SO4 (MW 142 g) to water and diluting to a final
volume of 140.0 mL?
1. 0.00024 g
2. 0.24 g
3. 95 g
4. 0.48 g
5. 0.0095 g

answer; i believe that the correct answer is (a); a large rock being weathered by wind and rain;

(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