An ice cube is left on the kitchen counter. After some time, the ice cube melts into a small puddle of water. According to the law of conservation of mass, how does the mass of the puddle of water compare to the mass of the original ice cube

Mass of the water is equal to the mass of ice

Explanation:

When ice melts, the mass remains the same even though its volume decreases leading to a decrease in density of water.

The mass remains the same because according to the law of conservation of mass, mass can neither be created nor destroyed. Since mass is neither created nor destroyed in the process of melting, the mass of water must remain the same.

(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