A hunk of cast concrete with a weight of 10 N will float if it displaces 10

N of water
true or false

False

False.

In order for an object to float, it must displace a weight of water equal to or greater than its own weight.

To calculate the weight of the water displaced by an object, you can use the Archimedes' principle, which states that the buoyant force acting on an object submerged in a fluid is equal to the weight of the fluid displaced by the object.

In this case, the weight of the cast concrete is 10 N, so for it to float, it would need to displace at least 10 N of water. However, since it only displaces 10 N of water, the buoyant force acting on it would be equal to the weight of the water displaced, which is not enough to balance the weight of the concrete. Consequently, the concrete will sink rather than float.