Which of the following elements has the highest atomic mass? 1. helium: 2 protons and 2 neutrons 2. nitrogen: 7 protons and 7 neutrons 3. oxygen: 8 protons and 8 neutrons 4. hydrogen: 1 proton and no neutrons

what is the question?

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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