Answer:
a water bottle.
Explanation:
a water bottle drains an area of land, just pour a water bottle on a small land on the surface of the earth it'll be called drained.
I believe it's the the third one. :)
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Answer:
The answer is given below
Explanation:
u is the initial velocity, v is the final velocity. Given that:

a)
The final velocity of cart 1 after collision is given as:

The final velocity of cart 2 after collision is given as:

b) Using the law of conservation of energy:

Lean your shoulders back and your waist forwards. Use your arms as a counter weight.