* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Motion, Forces, and Energy
Survey
Document related concepts
Coriolis force wikipedia , lookup
Internal energy wikipedia , lookup
Modified Newtonian dynamics wikipedia , lookup
Seismometer wikipedia , lookup
Fictitious force wikipedia , lookup
Newton's theorem of revolving orbits wikipedia , lookup
Rigid body dynamics wikipedia , lookup
Relativistic mechanics wikipedia , lookup
Equations of motion wikipedia , lookup
Centrifugal force wikipedia , lookup
Classical mechanics wikipedia , lookup
Work (thermodynamics) wikipedia , lookup
Mass versus weight wikipedia , lookup
Classical central-force problem wikipedia , lookup
Centripetal force wikipedia , lookup
Transcript
Motion, Forces, and Energy 4th Grade Science S4P3 Students will demonstrate the relationship between the application of a force and the resulting change in position and motion on an object. Motion, Forces, and Energy • GPS: S4P3 Students will demonstrate the relationship between the application of a force and the resulting change in position and motion on an object. Motion, Forces, and Energy • • • Main Idea: Objects move when they change their position. A frame of reference must be established. What frame of reference do we use in these?: 1. Clock 2. Sunset 3. Base runner in baseball Motion • Motion is a change in position of an object. • Things can move quickly or slowly. Speed • Speed is the distance an object moves in a certain amount of time. • Distance divided by time = D/T • Need to know the distance and the time to calculate speed. • Examples: 60miles/hour, 50 yards /second Velocity • Velocity is a measure of two things: the speed an object is moving and the direction an object is moving • Velocity = speed + direction • Example: An airplane is flying 500 mph/West Acceleration • Objects in motion often change their speed. • They can speed up or slow down. • They can change their direction. • Any change in the speed or direction of a moving object is called acceleration. How Do Forces Affect Motion? • Forces can be a push or a pull. • Forces can be big or small. • Forces make object start moving, stop moving, slow down, speed up, or change direction. • Forces are measured in units called newtons. • Forces game Balanced vs. Unbalanced Forces • If forces are balanced there is no change in the motion of an object • If forces are unbalanced there is a change in the motion of an object Gravity • Gravity is pulling you toward Earth’s surface. • Gravity pulls two objects with mass together – gravitation. • The force of gravity between objects depends on two things – mass and how close together the objects are • More mass = stronger gravitational pull • Closer together = stronger gravitational pull • Gravity is everywhere in the universe • What goes up – must come down. Weight • Weight is a measure of force. • It is the amount of gravity acting on an object. • How does your weight change if you should visit the Moon, Jupiter, Mars, or Saturn? • Astronauts feel weightless when they do not feel the pull of gravity. • Brain Pop on Gravity Friction • Friction is a force that acts in the opposite direction of motion • It slows down objects when two surfaces rub together • The amount of friction depends on the type of surface • More friction = rough surfaces; examples? • Less friction = smooth surfaces; examples • Friction between the air and an object is called air resistance • Friction game Inertia • An object at rest will stay at rest unless there is a force that acts upon it. • An object in motion will stay in motion unless there is a force that acts upon it. • This is why we wear seatbelts! • Brain Pop – Newton’s Laws Newton’s Laws of Physics • Newton’s First Law: The first law says that an object at rest tends to stay at rest, and an object in motion tends to stay in motion, with the same direction and speed. Motion (or lack of motion) cannot change without an unbalanced force acting. Newton’s Laws of Physics • Newton’s Second Law: The second law says that the acceleration of an object produced by a net (total) force is directly related to the magnitude of the force, the direction as the force, and inversely related to the mass of the object. • More force = more acceleration • More mass = less acceleration Newton’s Laws of Physics • Newton’s Third Law: The third law says that for every action (force) there is an equal and opposite reaction (force). • Forces are found in pairs. • Example: Sitting in a chair your body exerts a force downward and the chair needs to exert an equal force upward or the chair will collapse. What is work? • Work is done when a force is used to move an object a certain distance. • To do work, a force needs to push or pull on an object and the object needs to move in the direction of the force. Energy • In science, energy is the ability to do work. • Energy is needed to apply a force to an object to make it move. • Energy is needed to make matter change. • Energy is what makes the motion and change happen. Forms of Energy Energy Can Change Form • Energy does not always stay in one form. • Energy can change form. • Energy can be passed from one object to another. • Potential energy is stored energy – a lump of coal, an unused battery, a piece of candy • Kinetic energy is energy a moving object has – a running person, a burning candle, a falling ball. Motion, Forces, and Energy • Energy is all around us. • Forces are used to change motion. • Energy comes in many different forms and can be changed from one form to another. • Energy allows you and other objects to do work. • Knowing about energy can help us use it wisely!