Which of the following is the best example of chemical weathering?

(a) limestone rocks dissolving in water
(b) plant roots growing through concrete and splitting it
(c) waves carrying sand away from a beach
(d) a large rock splitting into pieces because of ice

A. Limestone rocks dissolving in water

Explanation:

B: This is a physical change; it changes an object physically rather than chemically. It does not change the composition of the concrete, only the shape.

C: This is also a physical change because the water is just dragging sand with it, but not actually changing the composition of it.

D: Similar to option B, this is an example of physical weathering because the ice only divides the rock into different parts but doesn't change the composition or complexity of it.

(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