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Individual. Net. 5 N. force = a push or a pull. 3 N. Unit of Force = Newton. net force = vector sum of all forces on object. 4 N. net force =. Individual Forces. Newton’s 1 st Law: object – stays at rest – or constant speed in a straight line – if no net force.
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Individual Net 5 N force = a push or a pull. 3 N Unit of Force = Newton • net force= vector sum of all forces on object 4 N net force= Individual Forces Newton’s 1st Law: object – stays at rest – or constant speed in a straight line – if no net force. Ch 4. Forces & Newton’s Laws of Motion 4 N 10 N Inertia = tendency of object to stay at rest – or constant speed in a straight line – if no net force. Net Force 6 N
Mass(m) is the amount of “stuff” in an object free-body-diagram represents object & forces Unit of Mass: kilogram (kg) Newton’s 2nd Law: Acceleration – proportional to Force – inversely proportional to mass Net force: 275 N + 395 N – 560 N = +110 N along the + x axis Units Acceleration: mass of car = 1850kg Unit of Force = Newton
Net force: forces
Newton’s 3rd Law: Action = Reaction Force from body-A to body-B = Force from body-B to body-A Magnitude of force is 36 N. Mass of spacecraft is 11,000 kg. Mass of astronaut is 92 kg. What are the accelerations?
Newton’s Law of Gravitation Weight = gravitational force earth attracts object masses m1 and m2separated by distance r, gravitational force 12 kg 25 kg 1.2 m On earth’s surface
Normal Force from surface to object Apparent Weight = normal force on scale by man true weight apparent weight
Frictional Force static friction coefficient of static friction. coefficient of kinetic friction = 0.05 mass = 40kg What is the kinetic frictional force? After motion begins coefficient of kinetic friction
Equilibrium Tension Force Cables and ropes transmit forces through tension. Equilibrium • Reasoning Strategy • select an object in equilibrium • draw free-body diagram for object & forces • choose x,y axes • resolve forces into x,y comps • apply equilibrium equations • solve for unknown quantities
Non-Equilibrium When an object is accelerating, it is not in equilibrium. you are given m,a,R,D