a glass block weighs 25N in air . when whole immersed in water, the block weighs 15N. calculate the relative density of glass
1000 * 9.81 * Vol = 25-15 = 10 N
so
Vol is about .001 m^3
25/.001 = 25,000 N/m^3
or about 2500 kg/m^3
or about 2.5 times that of water
To calculate the relative density of the glass, we need to use the principle of buoyancy. The buoyant force acting on an object submerged in a fluid is equal to the weight of the fluid displaced by the object.
Given:
Weight of the glass block in air = 25 N
Weight of the glass block in water = 15 N
Step 1: Calculate the apparent weight of the block in water
Apparent weight = Weight in air - Buoyant force
The apparent weight of the block in water is equal to the weight of the block in air minus the buoyant force exerted by the water.
Apparent weight in water = 25 N - 15 N = 10 N
Step 2: Calculate the buoyant force
Buoyant force = Weight in air - Apparent weight in water
The buoyant force can be calculated by subtracting the apparent weight of the block in water from its weight in air.
Buoyant force = 25 N - 10 N = 15 N
Step 3: Calculate the weight of the water displaced
The weight of the water displaced is equal to the buoyant force.
Weight of water displaced = 15 N
Step 4: Calculate the volume of the block
The volume of the block can be calculated by dividing the weight of the water displaced by the density of water.
Density of water = 1000 kg/m³
Volume of the block = weight of water displaced / density of water
Volume of the block = 15 N / 1000 kg/m³ = 0.015 m³
Step 5: Calculate the relative density of the block
The relative density is the ratio of the density of the block to the density of water.
Relative density = density of block / density of water
Density of block = weight of block / volume of block
Density of block = 25 N / 0.015 m³ = 1666.67 kg/m³
Relative density = 1666.67 kg/m³ / 1000 kg/m³ = 1.6667
Therefore, the relative density of the glass block is approximately 1.6667.
To calculate the relative density of the glass block, we need to use the concept of buoyancy. Buoyancy is the upward force exerted by a fluid (in this case, water) on an object immersed in it.
The weight of an object in air is equal to the force exerted by gravity on it. In this case, the glass block weighs 25N in air.
When the glass block is immersed in water, it experiences an upward buoyant force. The weight of the block in water is equal to the force exerted by gravity minus the buoyant force. In this case, the glass block weighs 15N in water.
We can use the equation:
Weight in air = Weight in water + Buoyant force
Substituting the given values:
25N = 15N + Buoyant force
Rearranging the equation, we find:
Buoyant force = 25N - 15N = 10N
The buoyant force is equal to the weight of the water displaced by the glass block. In other words, it is equal to the weight of the volume of water that would occupy the same space as the glass block.
The relative density (also known as specific gravity) is defined as the ratio of the density of a substance to the density of a reference substance. In this case, the reference substance is water.
The density of a substance is given by the equation:
Density = Mass / Volume
Since mass is directly proportional to weight, we can use the weights to compare densities.
The density of water is 1 g/cm³ or 1000 kg/m³.
The density of the glass block can be calculated as follows:
Weight in air = Density of glass x Volume x Acceleration due to gravity
Weight in water = (Density of glass - Density of water) x Volume x Acceleration due to gravity
Substituting the known values:
25N = Density of glass x Volume x 9.8 m/s²
15N = (Density of glass - 1000 kg/m³) x Volume x 9.8 m/s²
Solving these two equations simultaneously will give us the relative density of the glass block.