# Buoyancy Force of a boat

#### disneygirl828

1. Homework Statement
A boat full of people lazily drifts along in Lake Superior. The boat has a mass, including people of 15,450kg.
A. What is the buoyant force?

B. What is the volume of the displaced liquid in cubic meters?

3. The Attempt at a Solution
A. Fb=mg
Fb=?
m=15,450kg
g= 10m/s
(15450kg)(10m/s)
=154500kg*m/s^2
B.
=154500m^3

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#### gneill

Mentor
1. Homework Statement
A boat full of people lazily drifts along in Lake Superior. The boat has a mass, including people of 15,450kg.
A. What is the buoyant force?

B. What is the volume of the displaced liquid in cubic meters?

3. The Attempt at a Solution
A. Fb=mg
Fb=?
m=15,450kg
g= 10m/s
(15450kg)(10m/s)
=154500kg*m/s^2
B.
=154500m^3
While "154500kg*m/s^2" is technically correct, it is usual practice to convert the "kg*m/s^2" units to its well-known designation "N" for Newtons, the unit of force.

The displaced water should be equivalent in weight to the weight of the boat. Your value for the volume of displaced water is too large. What is the density of water in kg/m3?

#### disneygirl828

While "154500kg*m/s^2" is technically correct, it is usual practice to convert the "kg*m/s^2" units to its well-known designation "N" for Newtons, the unit of force.

The displaced water should be equivalent in weight to the weight of the boat. Your value for the volume of displaced water is too large. What is the density of water in kg/m3?
so the volume of the displaced water would be 15450kg? How do you convert kg*m/s^2 to Newtons?

#### gneill

Mentor
so the volume of the displaced water would be 15450kg? How do you convert kg*m/s^2 to Newtons?
The volume of the displaced water would be that volume of water which has a mass of 15450kg. To find that volume you will need to know the density of water (kg/m3).

The Newton is defined to be 1 kg*m/s2.

#### disneygirl828

Thank you SO much :)