click below

click below

Normal Size Small Size show me how

# Unit2ContactForces6

### Contact Forces, Newton's Laws of Motion, Kinetic Energy

Term | Definition |
---|---|

force | push or pull |

contact force | A force that is exerted only when two objects are touching. (examples: friction, elastic forces, applied force, and normal force--opposite of gravity) |

Newton's 1st Law of Motion | a physical law stating that an object at rest tends to stay at rest and an object moving in a straight line at a constant speed tends to continue moving that way |

inertia | Tendency of a moving object to keep moving in a straight line or an object at rest to stay at rest |

balanced forces | when two equal forces are applied to an object in opposite directions |

unbalanced forces | Forces that cause an object to change its motion (speed or direction) |

Newton's 2nd Law of Motion | a physical law that states that an object's acceleration depends on the object's mass and the amount of net force applied to it (more mass = less acceleration; more force = more acceleration) |

mass | the amount of matter in an object |

acceleration | change of speed (velocity) per unit of time (Note: acceleration due to gravity is 9.8m/s-squared--or m/s/s--for every second an object falls |

Newton's 3rd Law of Motion | a physical law that states that for every action there is an equal and opposite reaction (exactly 2 objects) |

action force | the initial push or pull of one object on another object |

reaction force | the push or pull of a second object back on the object that started the push or pull |

potential energy | Stored energy (measured in Joules) |

kinetic energy | energy in motion (measured in Joules) |

speed | distance divided by time |

velocity | speed and direction |

momentum | mass x speed |

law of conservation of energy | energy is neither created nor destroyed (but can be transferred or transformed into other types of energy) |

KE ∝ m | kinetic energy is directly proportionate to mass (as mass increases |

KE ∝ v^2 (velocity squared) | kinetic energy equals the square of the speed of an object (as velocity (speed + direction) increases |

PE ∝ m AND PE ∝ height | potential energy is directly proportionate to mass or height |

linear graph | a line graph in which the data points yield a straight line (KE ∝ m |

quadratic graph | a line graph in which the data points yield a sloped line or parabola (only positive numbers for KE) (KE ∝ v^2) |

independent variable | the one factor that is changed (manipulated) by the experimenter (cause) |

dependent variable | The outcome factor (result); the variable that may change in response to manipulation of the independent variable.(effect) |