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Vocab unit 4
Science
Term | Definition |
---|---|
Speed | Movement from place to another over time ; distance divided by time |
Average | Time it takes to travel the whole distance |
Instatntateus speed | Speed at an instant of time |
Velocity | Speed of an object and it's direction of motion |
Acceleration | Change in velocity divided by the amount of time needed for the change to occur |
Force | A push or a pull |
Newton's first law | Object at rest or in motion remains unless acted upon by another force |
Newton's second law | The speed of an object (acceleration is directly proportional to the force acting on it |
Newton's third law | When a force is exerted on an object , the object exerts an equal and opposite force on the first |
Friction | Force that racist motion between two touching surfaces and always acts opposite to the direction of motion |
Inertia | Tendency to resist in motion |
Mass | The amount of matter in an object |
Work | Applied forces causing an object to move in the direction of the force |
Machine | A device with moving parts that works together to accomplish a task |
Pulley | A object like a grooved wheel with a rope running thru the groove bad changes the direction of the input force |
Lever | A stiff structure that rotates around a fixed point called fulcrum |
Inclined plains | A sloped surface |
Wedge | Moving of an inclined plane |
Screw | The threads of screw are one long , continuos inclined plane ( wedge) and changes the direction of force |
Simple machine | Uses only one movement |
Compound machine | A combination of simple machines |
Mechanical advantages | The ratio of an output to input force |