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Physics Chapter 6 - Applications of Newton's Laws
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Gravity
Terms in this set (15)
Big Ideas
1. Friction is a force exerted between surfaces in contact
2. springs exert a force proportional to the amount of stretch or compression
3. a system is in translational equilibrium when the total force acting on it is zero
4. an object in circular motion accelerates toward the center of the circle
Friction
the force needed to overcome to get an object at rest to move
Ff = (MUs/k)(Fn)
Kinetic Friction
the friction that is produced when surfaces slide against one another, denoted by Fk
Rules of Thumb for Kinetic Friction
1. proportional to the magnitude of the normal force between surfaces
2. independent of the relative speed of the surfaces
independent of the area of contact between the surfaces
Static Friction
tends to keep two surfaces from moving relative to one another, typically stronger than kinetic friction because when surfaces are in static contact their microscopic hills and valleys nestle down deeply into one another, forming a strong connection between the surfaces, denoted by Fs
Rules of Thumb for Static Friction
1. It takes on any value between zero and the maximum possible force of static friction
2. it is independent of the area of contact between the surfaces
3. it is parallel to the surface of contact, and in the direction that opposes relative motion
Tension
ropes, strings, or anything that can pull an object while attached has a tension force
Pulleys
change the direction of tension in a string without changing its magnitude
Springs and Hooke's Law
a spring stretches from initial length (L) to it's final length (L + x)
F = +/- (k)(x)depending on x direction
k represents the force constant, measured in N/m
Ideal Springs
springs that are massless and exactly follow Hooke's Law
Translational Equilibrium
when the net force acting on an object is zero
(sum)->F = 0
Connected Objects
[ 2 ]-->T---T<--[ 1 ]--->F
Box One
F - T = (m1a1) = m1a
Box Two
T = (m2a2) = m2a
Circular Motion
a force is required to change the speed, direction, or both
force acts towards the center of a circle, which means that it accelerates to the middle of the circle, known as centripetal acceleration
Calculating the Centripetal Acceleration
Aave = (->v2 - ->v1) / (delta t)
Centripetal Force
Fcentripetal = (mass)(velocity^2 / radius)
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