Unit 5 Overview
Important Ideas to Consider in this Unit (aka review of past info)
- isolated systems: a group of objects that interact with each other but not with any objects outside of the system
- no flow of mass in or out of the system
- velocity: ratio of displacement of an object during a time interval (Δx/Δt)
- magnitude/ steepness of the slope determines how fast the object is going
- includes direction
- if the sign of the slope is positive, then the object is traveling in the positive direction (usually right -->)
- if the sign of the slope is negative, then the object is traveling in the negative direction (usually left <--)
- collision: two (or more) objects exert forces on each other in a relatively short time
Momentum |
Graphical Representation (LIL Chart) |
Equations
https://giphy.com/explore/conservation-of-momentum
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Conservation of Momentum
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Impulse
Equations
Graph
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Relating Momentum --> Energy, Forces, and Kinematics
Momentum Impulse Theorem (J = F * Δt = ΔP = P(final) - P(initial))
- Force and time involved
- Reminder of Different types of Forces
- Contact
- Normal Force = two surfaces in contact preventing them from passing through each other (perpendicular to the surface)
- Spring Force = force between compressed stressed string with object attached (opposite direction of stretch/ compression)
- Friction Force = resistive force when the surface of 2 objects when they rub together (opposite of desired direction the object wants to slide)
- Applied Force = direct push/pull on object (any direction)
- Tension Force = push/pull transmitted through a rope/ cable/ wire and the object attached (direction of the rope)
- Non-Contact
- Gravity = attractive force between two objects with mass
- object on Earth --> acts on object toward center of the Earth
- Gravity = attractive force between two objects with mass
Energy (1/2 mv(initial)^2 = 1/2 mv(final)^2)
- related to determining velocity
- i.e. final velocity of an object after it rolls down a hill involves both gravitational potential energy and kinetic energy
- mgh = 1/2 mv^2
- i.e. final velocity of an object after it rolls down a hill involves both gravitational potential energy and kinetic energy
- is kinetic energy conserved or not??
- if conserved, can set initial kinetic energy equal to final kinetic energy (elastic collision, isolated system)
- if not conserved, cannot use initial kinetic energy equal to final kinetic energy equation because energy lost to dissipative forces (i.e. sound, heat)
Kinematic Equations (vf^2 = vi^2 + 2aΔx)
- involved in relating velocity to change in position and acceleration