In which direction does a buoyant force act on an object? O A. Up
O B. Opposite to its motion
O C. Right or left
O D. Down

I THINK the answer is A - Up.

Explanation: The buoyancy force always points upwards because of the pressure of a fluid increases.  If the buoyant force is less than the object's weight, the object will sink. You can calculate the buoyant force on an object by adding up the forces exerted on all of an object's sides.

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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i don't understand. explain it clearly