click below

click below

Normal Size Small Size show me how

# Astronomy 1400 test2

### Astronomy 1400 test2 4,5,6,7

Question | Answer |
---|---|

What is the difference between speed, velocity, and acceleration? what are their units? | 1--Speed-- how fast and object is moving (distance/time) 2--Velocity--speed and direction 3--Acceleration--Change in objects velocity |

Know the accomplishments of Sir Isaac Newton that we discussed in class. | a. Explained all mechanics both celestial and earthly (Laws of motion and Force of Gravity) b. Invented Calculus c. Derives, corrects, expands Kepler’s Laws d. Wrote Philosophiae Naturalis Principia Mathematica |

What are Newton’s Three Laws of Motion? Give some examples of Newton’s laws at work. 1 | a. 1) A body at rest or in motion at a constant speed along a straight line remains in that state unless acted upon by an outside force. |

What are Newton’s Three Laws of Motion? Give some examples of Newton’s laws at work. 2 | b. 2) A net force changes an objects momentum, accelerating it in the direction of the force. Force= rate of change in momentum (momentum= mass x velocity) For constant mass: force=mass x acceleration so F=ma |

What are Newton’s Three Laws of Motion? Give some examples of Newton’s laws at work. 3 | c. 3) Whenever one body exerts a force on a second body, the second body exerts an equal and opposite force on |

What is the mathematical definition of momentum and angular momentum? | a. momentum= mass x velocity b. Angular momentum- momentum in spinning = mass x velocity x radius |

5. Explain briefly as we did in class how Newton’s Laws lead to the law of conservation on momentum. | a. An objects momentum won’t change if object is left along b. But a force can change an object’s momentum c. However, an = and opposite force changes some other objects momentum by an = and opposite amount |

6. What is angular momentum and torque? What is the law of conservation of angular momentum? | a. Torque- anything that causes change in angular momentum b. Conservation of angular momentum: As long as there is no external torque, the total angular momentum of a set interacting objects cannot change. |

7. Do we need to constantly fuel planets to spin and revolve? Do spacecraft constantly need fuel for propulsion through space? Why or why not? | a. No since there is no drag in space the objects just keep moving in the way that they were initially pushed |

8. What is the law of conservation of energy? | a. Energy can not be created nor destroyed |