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11 Cards in this Set
- Front
- Back
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Forces do not always cause motion Are what cause any change in the velocity of an object |
Concept of force |
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Forces |
Interaction with an object by means of muscular activity and some change in the object's velocity |
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Contact forces |
They involve physical contact between two objects |
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When a coiled spring is pulled, the spring stretches When a stationary cart is pulled the cart moves When a football is kicked, it is both deformed and set in motion Force exerted by gas molecules on the walls of a container Force exerted by your feet on the floor |
Examples of contact forces |
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Field forces |
Does not involve physical contact between two objects.act through empty space |
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The gravitational force of attraction between two objects with mass The electric force that one electric charge exerts on another The force a bar magnet exerts on a piece of iron |
Exampesof field forces |
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Newton N = 1kg m/s2 N = 1/4 lbr 1lbr = 1 slug ft/s2 |
Si unit of force |
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Newtons first law - law of inertia |
When no forces act on an object, it remains at rest or moves in a straight line with constant speed |
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Inertia |
The tendancy of any object to resist any attempt to change its velocity |
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Newtons second law - law of acceleration |
The acceleration or an object is directly proportional to the net force acting on it and inversely proportional to its mass |
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First condition of equilibrium |
The acceleration of the object is zero, the net force on the object is zero |
