A rock weighs 140 N in air and has a volume of 0.00273 m3. What is its apparent weight when sub-
merged in water? The acceleration of gravity is 9.8 m/s2 . Answer in units of N.
If it is submerged in a liquid with a density exactly 1.9 times that of water, what will be its new apparent weight?
Answer in units of N.
The weight of water displaced is
density of fluid * g * volume of fluid displaced
the density of water is about 1000 kg/m^3
so buoyant force up in water =
1000 * 9.8 * .00273
= 26.75 Newtons
so in water it will weigh
140 - 26.75 = 113 N
for the second part use 1900 kg/m^3 for the density of the fluid
apparent weight= true weight-bouyancy
= 140N- weight of water displaced
= 140N- densitywater*g*volume
but..how do i get the weight of water displaced? i don't get that part. because if i do
140- (.00273*9.8*5232.86) =0
To find the apparent weight of the rock when submerged in water, we need to understand buoyancy. Buoyancy is the upward force exerted on an object submerged in a fluid. The magnitude of this force is equal to the weight of the fluid displaced by the object.
1. First, let's find the weight of the water displaced by the rock.
The density of water is roughly 1000 kg/m^3. Given the volume of the rock (0.00273 m^3), we can calculate the mass of the water displaced:
Mass = Density * Volume = 1000 kg/m^3 * 0.00273 m^3
2. Next, let's find the weight of the water displaced by the rock.
Weight = Mass * Acceleration due to gravity (g)
3. Now, let's subtract the weight of the water displaced from the weight of the rock in air to find the apparent weight of the rock when submerged in water:
Apparent Weight = Weight in Air - Weight of Displaced Water
For the given data:
1. Weight in Air (rock) = 140 N
2. Density of Water = 1000 kg/m^3
3. Volume of Rock = 0.00273 m^3
4. Acceleration due to gravity (g) = 9.8 m/s^2
Now, let's calculate the apparent weight of the rock when submerged in water:
1. Calculate the weight of the water displaced:
Mass = Density * Volume = 1000 kg/m^3 * 0.00273 m^3
2. Calculate the weight of the displaced water:
Weight of Displaced Water = Mass * g
3. Calculate the apparent weight:
Apparent Weight = Weight in Air - Weight of Displaced Water
For the given data:
1. Weight in Air (rock) = 140 N
2. Density of Water = 1000 kg/m^3
3. Volume of Rock = 0.00273 m^3
4. Acceleration due to gravity (g) = 9.8 m/s^2
Now, let's calculate the apparent weight of the rock when submerged in water:
1. Calculate the weight of the water displaced:
Mass = Density * Volume = 1000 kg/m^3 * 0.00273 m^3
2. Calculate the weight of the displaced water:
Weight of Displaced Water = Mass * g
3. Calculate the apparent weight:
Apparent Weight = Weight in Air - Weight of Displaced Water
Substituting the given values:
1. Mass = 1000 kg/m^3 * 0.00273 m^3
2. Weight of Displaced Water = Mass * g
3. Apparent Weight = 140 N - Weight of Displaced Water
To find the new apparent weight when the rock is submerged in a liquid with a density exactly 1.9 times that of water:
1. Calculate the density of the new liquid:
Density of New Liquid = 1.9 * Density of Water
2. Repeat the above steps using the density of the new liquid instead of water to find the apparent weight when submerged.