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Physical Scienc ch11
Forces and Energy
Question | Answer |
---|---|
friction | the force that opposes the motion of one object moving past another |
force | any push or pull from one object to another. The units of force are Newton(N) and the Pound (lb) |
efficiency | is the ratio of input to output energy, usually written as a percentage |
work | is the measurement of the energy used to perform a task -- this can change the amount of energy it has |
position | the location of an object |
law of conservation of energy | the idea that energy cannot be created or destroyed -- it can only change form |
fulcrum | is a pivot point for a lever |
velocity | the measurement that combines the speed and direction of a moving object. |
momentum | is the product of mass times the velocity --the more it has the easier to move other objects |
speed | is how fast an object`s position changes over time |
How does the force of gravity between 2 objects affect its mass and distance? | Gravity -- increases with mass and decreases with distance |
What does friction produce as 2 or more objects come into contact? | heat |
What is Newton's 2nd law of motion? | It states that force is equal to mass X acceleration |
What is potential energy? | energy that is stored -- like a plate on a lower shelf versus a plate on a higher shelf |
What is kinetic energy? | It is the energy of a moving object. |
What are balanced forces? | these forces act on an object without changing its motion (can you think of an example) |
What are unbalanced forces? | these are forces that cause an object to change its motion (think of an example) |