. Law of Conservation of Momentum
(for a perfect system)
Total Momentum Before Total Momentum After
(20kg)(2m/s) + (10kg)(-1m/s) = (20kg)(0.5m/s) + (10kg)( 2m/s)
40kg m/s + -10kg m/s 10kg m/s + 20kg m/s
30kg m/s 30 kg m/s
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i am pretty sure it is c because when people are closer together, they cannot move as freely. picture being in a mostly full elevator, for instance. the people are right next to you, and you can barely move.

when heated, the valance electrons increased their speed and transferred the heat from electron to electron.   i just took the test.

im srry but ur wrong the answer is d a smooth rock, some red dirt, and an empty bird's nest.

force required to detach it is given by

charges are taken to be fundamental charge

now we have

so above is the minimum distance at which it will detach