Objects comprised of material that is denser than water tend to sink; objects with a lighter density tend to float. Since air is lighter than water, hollow objects can float if their total density is less than water. Preventing objects from absorbing water is important.Continue Reading
Liquids have different densities, and objects will sink if they are of a greater density than the substance they are placed in; dense objects, including rocks and pieces of metal, will sink if placed in water. Lighter objects, including most types of wood, will float.
Dense material can be made to float if it contains enough air, which has a density much lower than that of water. A metal ball that is hollowed out and appropriately sealed can have a density less than water, which will cause it to float. Heavier metals need more air, but any material can be made to float.
Boats float by taking advantage of this principle, and they can be made of woods that are denser than water. The large hull of a boat holds a significant amount of air, which lowers its total density. If the boat is loaded too heavily or if water enters the hull, the boat can sink if its density gets too high.Learn more about Motion & Mechanics
The relation between time and motion is that of conceptual inseparability: motion only occurs through time, and time only passes in a universe in which objects move. In physics, motion refers to the change of position of an object through time. Time is a measure of change between two states; in the material universe, change in matter occurs through motion.Full Answer >
Some examples of static friction between two substances or objects are: glass on glass, tire on concrete, tire on snow, tire on a wet surface and steel on steel. Friction is the force between two objects in contact with each other that will resist an attempt to move them. Static friction is the force that will resist the movement up until it is overcome by a greater force and the motion occurs.Full Answer >
The law of the pendulum, discovered by Galileo Galilei, states that swinging objects follow the same path and have a period between swings that remains constant. Galileo attracted immediate attention for the discovery, which was later used in clock regulation.Full Answer >
Gravitational pull is the invisible force that causes massive objects to pull other objects towards them. For instance, when a person jumps up in the air, it is the earth’s gravitational pull that causes him to return to the ground. All massive objects have gravity, and the bigger they are, the more gravitational pull they produce.Full Answer >