A dense plastic toy of mass 1.8 kg is floating just beneath the surface of a pond. What is the buoyant force on it?
Answer in units of N.
bet it is 1.2*9.8 Newtons. If it were less it would sink, if it were more, it would be on the surface.
You mean 1.8 * 9.81 N
To find the buoyant force on the plastic toy, we need to use Archimedes' principle. Archimedes' principle states that the buoyant force on an object submerged in a liquid is equal to the weight of the liquid displaced by the object.
To calculate the buoyant force, we need to find the weight of the liquid displaced by the toy. The weight of an object can be calculated using the formula:
weight = mass * acceleration due to gravity
The acceleration due to gravity is approximately 9.8 m/s^2 on Earth.
In this case, the mass of the toy is given as 1.8 kg. So, the weight of the toy can be calculated as:
weight = 1.8 kg * 9.8 m/s^2
Next, we need to calculate the volume of the liquid displaced by the toy. The volume of a submerged object can be found using its density and mass:
volume = mass / density
Since the toy is floating just beneath the surface, it displaces its own volume of water. The density of water is approximately 1000 kg/m^3.
Now, we can calculate the buoyant force using the weight of the liquid displaced:
buoyant force = weight of liquid displaced
Let's plug in the values and calculate the buoyant force:
weight = 1.8 kg * 9.8 m/s^2 = 17.64 N
volume = 1.8 kg / 1000 kg/m^3 = 0.0018 m^3
buoyant force = 17.64 N
Therefore, the buoyant force on the plastic toy is approximately 17.64 N.