# Will the scuba diver sink or float

## Homework Statement

A scuba diver and her gear displace a volume of 65.0L and have a total mass of 68.0kg. What is the buoyant force on her and will the diver float or sink.

FB=pFVg

## The Attempt at a Solution

The first thing I did was find the weight of the diver as w=mg=68.0kgX9.8m/s2=670N
Then I tried to find the buoyant force using archemedes' principal (FB=pH20Vg
I used the given density as 103 kg/m3, the volume of water displaced is 65.0L, which I converted to m3 by using the factor of 103L/1m3 to get 6.5X104m3. The equation then becomes
(103kg/m3)(6.5X104m3)(9.8m/s2)
and I get 6.4X108N, which is greater than mg, so the diver would float.

I'm wondering if this is correct or not

Edit: Forgot to mention, I'm not too concerned with sigfigs, as long as the answer is withing a reasonable variance the teacher will give me credit.

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That buoyant force is awfully large. Check your L to m^3 conversion

berkeman
Mentor

## Homework Statement

A scuba diver and her gear displace a volume of 65.0L and have a total mass of 68.0kg. What is the buoyant force on her and will the diver float or sink.

FB=pFVg

## The Attempt at a Solution

The first thing I did was find the weight of the diver as w=mg=68.0kgX9.8m/s2=670N
Then I tried to find the buoyant force using archemedes' principal (FB=pH20Vg
I used the given density as 103 kg/m3, the volume of water displaced is 65.0L, which I converted to m3 by using the factor of 103L/1m3 to get 6.5X104m3. The equation then becomes
(103kg/m3)(6.5X104m3)(9.8m/s2)
and I get 6.4X108N, which is greater than mg, so the diver would float.

I'm wondering if this is correct or not

Edit: Forgot to mention, I'm not too concerned with sigfigs, as long as the answer is withing a reasonable variance the teacher will give me credit.
How much does 65L of water weigh?

• 1 person
Borek
Mentor
Salt water, or fresh water?

Not that it matters much in this case, but it matters when you dive.

berkeman
Mentor
Salt water, or fresh water?

Not that it matters much in this case, but it matters when you dive.
Good point! SteamKing
Staff Emeritus