# Physics Test Notes on Forces

Pages: 4 (1249 words) Published: June 10, 2013
Physics Notes

* If the vector of all sums is precisely zero the object could be still moving * IF an elevator fell , the passengers would be trapped to the ceiling of the elevator seeing as there is no air resistance , false * Constant speed = no acceleration = sum of all net forces is zero * An object in orbit around the earth is not truly weightless * Sitting half as far away from your class mate the gravitation force is four times as strong. (re2) * Newton’s First Law- inertia an object that is not moving will remain at rest (ex: and apple hanging from a tree) * The reason you head feels like it jerks back ward is when pulling away from a stop sign is due to Newtons first law * If two forces that are identical in strength but exactly opposite in direction act on the same object that object will not necessarily be motionless * When drawing a FBD, the net force must not be included * 2 people pushing an object across a frictionless surface will result in twice the acceleration than if only one was pushing. Assume the object slides in both cases and both people push with same force (true) *

Types of forces:
* Dynamics: the study of motion
* No movement forces are balanced
* Applied Force: a force that results when one object makes contact with another (pushes or pulls it) * Tension: a pulling force, with a rope/ string
* Normal force: only when in contact with something ie. The ground. Points away from surface * Friction: opposes the sliding of two surfaces cross one another. Act opposite to the motion/ attempt at motion (electrostatic forces) * Force diagram-show all forces acting on object

Newtons first Law:
* Inertia: proportional to mass of the object, every object wants to maintain their state of motion, resists change in motion (stay in constant motion) * Law: an object will remain at rest or continue to move at a constant velocity when the net force on the object is 0....

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