1 / 74

FORCE AND MOTION

FORCE AND MOTION. 1. Earth and everything on it are affected by FORCES . 2. A force is a PUSH OR A PULL that causes an object to move, STOP , change direction, SPEED up, or slow down. It is measured in units called NEWTONS (N) after Sir Isaac Newton.

louiseduncan
Download Presentation

FORCE AND MOTION

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. FORCE AND MOTION

  2. 1. Earth and everything on it are affected by FORCES. 2. A force is a PUSH OR A PULL that causes an object to move, STOP, change direction, SPEED up, or slow down. It is measured in units called NEWTONS (N) after Sir Isaac Newton.

  3. Look closely at each picture. What would you do with it: push or pull? Drag it behind the green box in which it belongs (but make sure some of the picture sticks out!). Check your answers on the next page.

  4. 3. There are three forces on Earth every day that affect motion: friction, MAGNETISM, and gravity.

  5. What force is present in this picture: a push or a pull? In which direction will the object move? Which object will move and why?

  6. 4. Friction opposes or acts AGAINST motion. • It occurs when two objects RUB against each other. • ROUGHER surfaces have more friction than smoother surfaces. • Friction produces HEAT. • In Latin, fricare means “to RUB.” • It depends on the object's SURFACE (rough or smooth) , object's MASS (heavy or light), object’s SHAPE (aerodynamic), surface area of object (big or small) in liquids and gases, and how hard an object is pushed. • Air RESISTANCE is like friction. For example, the size of a parachute's canopy can affect how fast the parachute will touch ground. • Objects with MORE mass will have more friction. Two bricks will be harder to pull than one brick. Video: Friction 3:09

  7. What do the top arrows in each picture represent? What do the bottom arrows represent? In the top picture, which block will move faster and why? In the bottom picture, which block will move faster and why?

  8. LUBRICANTS will reduce friction. Examples include water, GREASE, wax, and motor oil. Without lubrication, moving parts of machines would slow down or stop very quickly. • WHEELS or rollers can also reduce friction. Heavier objects can be moved more easily across the floor if on wheels.

  9. Objects that are aerodynamic will allow less friction. Think of rockets and how they are shaped and cyclists and their helmets. They are ROUNDED so they can glide through the air with little resistance.

  10. 5. MAGNETISM is the ability of an object to push or pull on another object that has magnetic properties. • Magnetic force acts at a DISTANCE and cannot be SEEN. • Magnets have poles (NORTH AND SOUTH). • Unlike poles (N-S) ATTRACT or pull towards each other.

  11. Like poles (N-N or S-S) REPEL or push away from each other. • Magnetism is greater at the POLES. • The CLOSER the objects, the GREATER the magnetic force.

  12. IRON, nickel, and a few other metals are attracted to magnets. Not all metals will be magnetic. • A magnet produces a magnetic FIELD around itself and affects certain objects. Magnetic force can act without TOUCHING objects. • The needle of a compass moves because of Earth's MAGNETISM. Magnetic_Force_2_PPT[1].ppt

  13. Where is the force of magnetism the greatest in this picture and how do you know?

  14. 6. Gravity affects objects on Earth all the time. • It hold things to the SURFACE of the Earth. • It pulls objects (big or small) TOWARDS each other. • Gravity is WEAKER between smaller objects and larger for objects of greater mass. • The CLOSER objects are to each other, the greater the force of gravity. Video: What is Gravity 1:23 Video: Intro to Forces and Gravity 3:15

  15. Gravitational_Force_3[1].ppt • The gravity between Earth and anything on it is noticeable because the MASS of Earth is so large. The pull of Earth's gravity makes any object FALL TO THE GROUND. • As the moon goes around Earth, its gravity pulls on Earth causing WATER in the oceans to move towards the moon. This movement is called TIDES. • Earth's gravity also pulls on the MOON and keeps the moon moving around Earth. In the same way, the pull of the SUN keeps Earth moving around the sun.

  16. graph... This means that, wherever you are in the world, "down" is always towards the ground - even though your "down" isn't the same direction as anybody else's.

  17. Which force(s) do you see present in this picture?

  18. 7. Motion is the change of an object’s POSITION over a period of time. It is described in terms of position, direction, and speed. • Distance is the LENGTH traveled. It is measured in meters (m), kilometers (km), feet (ft), or miles (mi). • Distance from the REFERENCE point changes when the object moves.

  19. 7. Motion is the change of an object’s POSITION over a period of time. It is described in terms of position, direction, and speed. • Distance is the LENGTH traveled. It is measured in meters (m), kilometers (km), feet (ft), or miles (mi). • Distance from the REFERENCE point changes when the object moves. • Direction is the PATH that an object moves and can be determined by reading a COMPASS. It can be described using the terms north, SOUTH, east, west, RIGHT, left, FORWARD, toward, UP, down, or with degrees.

  20. Speed is a measure of how FAST an object is moving. To determine speed you must know TIME and distance traveled. • Time is how LONG it takes. It is measured in SECONDS (sec), MINUTES (min), or HOURS (hr). Motion_5[1].ppt video: Laws of Motion 17:28

  21. 8. In order to observe motion, you must first observe or determine an object’s POSITION, or its place or location. • Position can be described using points on a GRID • An object's motion depends on your FRAME of reference (a group of objects from which you can measure a position or motion).

  22. 1. What do the arrows represent in this picture? 2. What part of the map shows you direction? 3. What direction is the car on the left traveling? On the right? 4. What do the squares represent on this map?

  23. Position of an object is its LOCATION relative to another object (called the REFERENCE point). • Words that describe position include ABOVE, below, besire, BEHIND, ahead of, as well as the distance from the object. • An object is moving if its position CHANGES. • An object not moving is at REST.

  24. In what direction would you be traveling on a trip from Chicago to St. Louis? How would you know? Which city is the greatest distance from Chicago? What direction would you be traveling if you left Chicago for Des Moines?

  25. Motion • There are a few ways to describe the motion of an object: Speed Velocity acceleration

  26. Speed • One way to describe motion is speed. • Speed is a measure of the distance an object moves in a certain amount of time. • Speed is distance divided by time and is measured in m/sec or mph. • Speed is a measure of how fast an object is moving. • Motion is the change in position of an object over time when compared with a reference point.

  27. Velocity • Velocity is an object’s speed in a particular direction. • Examples: • 25 mph north • 23 meters per second west

  28. Point of Reference • Point of reference-your point of motion when you observe a motion

  29. Acceleration:is any change in velocity (speed and/or direction)* so when an object starts, stops, speeds up, slows down, or turns left/right, then it is ACCELERATING!

More Related