Introduction to Forces

Experiment! Make a prediction about what will hit the ground first, a piece of paper or a golf ball? Which one hit the ground first? What do you think will happen if the piece of paper is crumped into a small ball? What causes the objects to fall? Why don't they stay suspended in the air? What is a Force? A force is a push or a pull.Forces influence the motion of objects.There can be several different forces acting on a object at the same time.When one object pushes or pulls on another object, we say that the first object is exerting a force on the second object.Forces can cause an object to start moving, stop moving, or change direction. Types of Forces Gravity: The force that pulls objects towards the center of the Earth.Air Resistance: The force that acts in the opposite direction to objects moving in the air.Friction: A resistance force that an object encounters when moving across a surface. Check for Understanding A force that causes an apple to fall from a tree. gravity friction air resistance A force that causes cyclist to come to a stop. gravity friction air resistance The force an airplane encounters when traveling through the air. gravity friction air resistance The force a shuttle overcomes when leaving the Earth's atmosphere. gravity friction air resistance Practice Match the vocabulary word with the definition. Force A push or pull Air Resistance A force that acts in the opposite direction to object moving in the air. Friction The resistance force that an object encounters when moving over a surface. Gravity The force that attracts objects towards the center of the earth. Motion A change in position of an object over time. Pick which force is best represented by the arrow in the image. air resistance friction gravity air resistance friction gravity air resistance friction gravity air resistance friction gravity air resistance friction gravity air resistance friction gravity Describe what forces are being acted upon the box.