{
 "source": "https://peabody.kids/flashcards/phys-forces-motion",
 "id": "phys-forces-motion",
 "title": "Forces and Motion",
 "category": "science",
 "subject": "Physics",
 "levels": [
  "3-5",
  "6-8"
 ],
 "description": "Pushes, pulls, gravity, friction and Newton's laws in simple words.",
 "tags": [
  "forces",
  "motion"
 ],
 "frontLabel": "Question",
 "backLabel": "Answer",
 "cards": [
  [
   "What is a force?",
   "A push or a pull"
  ],
  [
   "What unit measures force?",
   "The newton"
  ],
  [
   "What force pulls objects toward Earth?",
   "Gravity"
  ],
  [
   "What does friction do?",
   "Slows or stops objects that slide against each other"
  ],
  [
   "Which surface has more friction, ice or sandpaper?",
   "Sandpaper"
  ],
  [
   "How can you reduce friction?",
   "Use oil, wheels or a smooth surface"
  ],
  [
   "Types of friction",
   "Static, sliding, rolling and fluid"
  ],
  [
   "Static friction",
   "Friction that keeps a resting object from moving"
  ],
  [
   "Sliding friction",
   "Friction between surfaces sliding over each other"
  ],
  [
   "Rolling friction",
   "Friction when an object rolls; usually smaller than sliding"
  ],
  [
   "Air resistance",
   "A force that slows things moving through air"
  ],
  [
   "Magnetic force",
   "A push or pull between magnets"
  ],
  [
   "Normal force",
   "The push of a surface upward on an object resting on it"
  ],
  [
   "Tension",
   "A pulling force through a rope or string"
  ],
  [
   "Applied force",
   "A force given to an object by a person or thing"
  ],
  [
   "Buoyant force",
   "The upward push of water on an object"
  ],
  [
   "Why does a feather fall slower than a rock in air?",
   "Air resistance affects it more"
  ],
  [
   "Would a feather and a hammer fall together on the Moon?",
   "Yes, with no air they fall at the same rate; astronaut David Scott showed this in 1971"
  ],
  [
   "Mass vs weight",
   "Mass is the amount of matter; weight is the pull of gravity on it"
  ],
  [
   "Is your mass different on the Moon?",
   "No; your weight is, because gravity is weaker"
  ],
  [
   "How much is gravity on the Moon compared to Earth?",
   "About one-sixth"
  ],
  [
   "Balanced forces",
   "Forces equal and opposite; no change in motion"
  ],
  [
   "Unbalanced forces",
   "Forces that change an object's motion"
  ],
  [
   "Inertia",
   "The tendency of objects to keep doing what they're doing"
  ],
  [
   "Why do you lurch forward when a car brakes?",
   "Your body's inertia keeps it moving forward"
  ],
  [
   "Newton's first law in short",
   "Objects at rest stay at rest and objects in motion stay in motion unless a force acts"
  ],
  [
   "Newton's second law in short",
   "More force means more acceleration; more mass means less"
  ],
  [
   "Newton's third law in short",
   "Every action has an equal and opposite reaction"
  ],
  [
   "Example of Newton's third law",
   "A rocket pushes gas down and the gas pushes the rocket up"
  ],
  [
   "Speed",
   "How fast something moves"
  ],
  [
   "Velocity",
   "Speed with a direction"
  ],
  [
   "Acceleration",
   "Changing speed or direction"
  ],
  [
   "Is a car turning at constant speed accelerating?",
   "Yes, because its direction is changing"
  ],
  [
   "Free fall",
   "Falling with only gravity acting"
  ],
  [
   "How fast do falling objects accelerate on Earth?",
   "About 9.8 meters per second every second"
  ],
  [
   "Terminal velocity",
   "The top speed of a falling object when air resistance balances weight"
  ],
  [
   "Projectile",
   "An object launched and moving through the air"
  ],
  [
   "Momentum",
   "How hard it is to stop a moving object: mass times velocity"
  ],
  [
   "Collision",
   "When two objects hit each other"
  ],
  [
   "Elastic collision",
   "Objects bounce and kinetic energy is kept"
  ],
  [
   "Inelastic collision",
   "Objects crumple or stick together and some energy changes form"
  ],
  [
   "Centripetal force",
   "A force pulling toward the center of a circular path"
  ],
  [
   "Centrifugal force",
   "The feeling of being pushed outward in a turn; really inertia"
  ],
  [
   "Orbit",
   "The curved path of one object around another due to gravity"
  ],
  [
   "Why do planets stay in orbit?",
   "Gravity pulls them toward the Sun while their motion carries them forward"
  ],
  [
   "Who described the law of gravity in the 1600s?",
   "Isaac Newton"
  ],
  [
   "Who showed that objects of different mass fall at the same rate in a vacuum?",
   "Galileo's ideas led there; later experiments confirmed it"
  ],
  [
   "Seat belts protect people by",
   "Slowing the body gradually and holding it in place"
  ],
  [
   "Airbags work by",
   "Spreading force over a longer time"
  ],
  [
   "Pressure",
   "Force spread over an area"
  ],
  [
   "Why do snowshoes help you walk on snow?",
   "They spread weight over a larger area"
  ],
  [
   "Torque",
   "A force that causes turning"
  ],
  [
   "Equilibrium",
   "A state in which forces are balanced"
  ],
  [
   "Speed formula",
   "Speed = distance divided by time"
  ],
  [
   "If you travel 100 km in 2 hours, your average speed is",
   "50 km per hour"
  ],
  [
   "Reference point",
   "A place or object used to describe an object's position"
  ]
 ]
}