Some objects float in water because the objects
A weigh less than the weight of the water they displace.
B have less mass when they are placed in water.
C have greater density than water
The correct answer is A: They weigh less than the weight of the water they displace.
To understand why this is the correct answer, we need to consider the concept of buoyancy. When an object is placed in a fluid, such as water, it experiences an upward force called buoyant force. This force is exerted by the fluid on the object and opposes the force of gravity.
According to Archimedes' principle, the buoyant force acting on an object is equal to the weight of the fluid displaced by the object. In other words, when an object is submerged in water, it pushes aside, or displaces, a certain volume of water. The weight of this displaced water exerts an upward force on the object.
For an object to float in water, the buoyant force must be greater than or equal to the force of gravity acting on the object. In other words, the weight of the water displaced by the object must be greater than or equal to the weight of the object itself.
If the object's weight is less than the weight of the water it displaces, it will experience a net upward force and float in water. This is because the buoyant force is greater than the force of gravity, enabling the object to stay afloat.
Therefore, the correct explanation is that objects float in water because they weigh less than the weight of the water they displace.