PhysicsLAB: 2004 Form B

The experimental diving bell shown above is lowered from rest at the ocean’ s surface and reaches a maximum depth of 80 m. Initially it accelerates downward at a rate of 0.10 m/sec² until it reaches a speed of 2.0 m/s, which then remains constant. During the descent, the pressure inside the bell remains constant at 1 atmosphere. The top of the bell has a cross-sectional area A = 9.0 m². The density of seawater is 1025 kg/m³.

	(a) Calculate the total time it takes the bell to reach the maximum depth of 80 m.

	(b) Calculate the weight of the water on the top of the bell when it is at the maximum depth.

	(c) Calculate the absolute pressure on the top of the bell at the maximum depth.

On the top of the bell there is a circular hatch of radius r = 0.25 m.

	(d) Calculate the minimum force necessary to lift open the hatch of the bell at the maximum depth.

	(e) What could you do to reduce the force necessary to open the hatch at this depth? Justify your answer.