Everyday Forces BY MR. V. CALZADA & MRS. SWANSON Vocabulary force friction magnetism gravitation Vocabulary A force is any push or pull that causes an object to move, stop, or change direction. Friction is a force that opposes, or acts against, motion when two surfaces rub against each other. Magnetism is the force of repulsion (pushing) or attraction (pulling) between poles of magnets. Gravitation is the force that pulls all objects in the universe toward one another. Forces An object starts to move, stops moving or changes direction only when a force acts on it. The Three Everyday Forces friction magnetism gravitation Friction Friction is a force that opposes, or acts against, motion when two surfaces rub against each other. Rough surfaces produce more friction than smooth surfaces do. Friction is a force that opposes, or acts against, motion when two surfaces rub against each other. Smooth surfaces produce less friction than rough surfaces do. Friction Magnetism Magnetism is the force of repulsion (pushing) or attraction (pulling) between poles of magnets. Magnetism Earth is one giant magnet! The Earths Magnetic Field Protect Us From Harmful Sun Radiation. Gravitation Gravitation is the force that pulls all objects in the universe toward one another. The strength of the gravitational force between two objects depends on two things: The mass of the two objects The distance between two objects Strength of Gravity