# Single Particle Dynamics/2nd Law

## Newton's Second Law

Motivation and statement of Newton's second law; difference between mass and weight.

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• Watch {}video clip from Lecture 6 (6:52 - 11:04)

Statement that F=m*a; definition of mass; superposition of forces; second law examples.

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Definition of force (F=ma); superposition principle; definition of impulse and average impulse; Newton's second law equations for force, acceleration, momentum.

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## Statics Problem

Statics problem of mass hanging from two angled strings solved and demonstrated.

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## Weight and Free Fall

Weight defined; weight on accelerating scales calculated; free-fall defined.

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• Watch {}video clip from Lecture 7 (0:00 - 9:16)

## Masses on a Frictionless Pulley

Acceleration and tension calculated for two masses suspended over a pulley.

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• Watch {}video clip from Lecture 7 (9:16 - 15:40)

## Interpretation of Masses on a Pulley

Results interpreted as masses become unbalanced; gain and loss of weight in free-fall.

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• Watch {}video clip from Lecture 7 (15:40 - 20:27)

## Tension in Revolving String

Calculation of tension at top and bottom of loop for mass swinging in vertical plane.

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• Watch {}video clip from Lecture 7 (20:27 - 26:53)

## Weightlessness During Free-Fall

Demonstration that a gallon of water is weightless in free fall during jump from table.

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• Watch {}video clip from Lecture 7 (26:53 - 31:09)

## Weightless Mass in Free-fall

Demonstration that barbell is weightless in free-fall, then very heavy on impact.

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• Watch {}video clip from Lecture 7 (31:09 - 39:28)

## Weightlessness Video

Video demonstration of the Vomit Comet and explanation of its cycle and conditions.

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• Watch {}video clip from Lecture 7 (39:28 - 50:00)

## Static Friction

Definition, including normal force; μs = ∠tan α proven; method for determining μs.

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• Watch {}video clip from Lecture 8 (0:00 - 7:01)

## Measuring Static Friction

Demonstration of dependence of μs on surface, but not surface area or mass.

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• Watch {}video clip from Lecture 8 (7:01 - 11:38)

## Friction in Pulley/Plane System

System of block sitting on inclined plane, connected to hanging block; calculation of conditions when block is falling or is static.

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• Watch {}video clip from Lecture 8 (11:38 - 20:50)

## Example of Pulley/Plane System

Numerical calculations for pulley/plane system, including interpretation and calculation of acceleration and tension.

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• Watch {}video clip from Lecture 8 (20:50 - 30:29)

## Pulley/Plane Demo

Demonstration of pulley/plane system; additional mass hangs, then falls; explanation of changing friction.

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• Watch {}video clip from Lecture 8 (30:29 - 36:22)

## Waterplaning and Air Tracks

Explanation of friction elimination by hydroplaning and air tracks, with brief demonstrations.

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• Watch {}video clip from Lecture 8 (36:22 - 41:41)

## CO2 Shuttle

Video of device that travels on cushion of CO2 on plate glass; friction so low a flea can pull a large book on the device.

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## Yardstick Puzzle

Moving two fingers towards each other under a yardstick causes alternating movement.

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• Watch {}video clip from Lecture 9 (48:13 - 50:06)

## Newton's Laws

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Newton's first law defined; Newton's second law defined (F = m*a); Newton's third law defined; inertial reference frames defined.

Forces acting on two blocks connected and suspended by strings. Solution not included.

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Reading a scale in an elevator.

## Newton's Laws of Motion

Newton's three laws of motion defined with a sentence each.

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## Force Laws

Newtonian induction; definition of Hooke's law; contact forces between surfaces; kinetic friction; static friction; fundamental forces of nature; definition of universal law of gravitation, with equation.

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## Second Law Methodology

Newton's Second Law in components; step-by-step method for solving second law problems.

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## Applying Newton's Second Law

Definition of a reference frame; relative and relatively inertial reference frames; law of addition of velocities, with example problem; acceleration in relatively inertial reference frames; principle of relativity; tension in a massless rope; equations of motion, with special cases; constraint conditions in pulley systems.

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## Experiment 3

Force modeling experiment setup and procedure.

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## Work on Sliding Box

4-part problem; finding work in terms of frictional force; stopping time; work to accelerate the box.

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## Forces and Reference Frames

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Forces acting on a passenger in a turning car. Solution not included.

Forces acting on systems of multiple bodies. Solution not included.

## Painter on a Platform

Force and acceleration.

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## Force and Velocity

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Force needed to accelerate a cart to a specified speed. Solution not included.

## Passenger in Car

Force acting on a passenger in a sharply turning car. Solution not included.

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## Sensation of Motion

Detecting motion from inside a windowless, soundproof vessel. Solution not included.

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## Experiment 3 Pre-Lab

Magnitude of force between two magnets as a function of distance.

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## Uniform Circular Motion

Forces acting on a mass connected to a rotating axle.

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## Experiment 5 Pre-Lab

Forces acting on a pivoted beam.

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## Experiment 5B Analysis

Motion of two unequal masses suspended by a string over a rod.

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## Conservation of Mechanical Energy

Motion of a small object that slides down a large sphere and hits the ground.

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## Static Friction Coefficient

Calculating μs by two methods.

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## Holding a Book Against a Wall

Free-body diagram and forces in pushing a book against a wall at an angle α.

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## Why Wide Tires?

Asks why race cars use wide tires, even though friction is independent of surface area.

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## Sliding Stick Across Fingers

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## Spring with Friction

Finding maximum extension, time to maximum velocity for spring extended on frictional surface.

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## Suitcase Dropped on Conveyor Belt

Kinetic vs. static friction and sign; magnitude of horizontal force on suitcase.

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## Two Blocks on Two Slopes

Two blocks connected over pulley, on separate slopes; find α of pulley, a, and T.

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## Second Law and Kinetic Energy

Relative motion and energy of two objects.

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## Ascending Jet

Motion of a jet airplane after takeoff.

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## Objects in Closed Boxes

Determining change in weight of person jumping and hummingbird taking off inside a closed box on a scale.

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## Ball in a Vertical Circle

Speed and tension at the top of the circle for ball swinging around.

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## Accelerating Car

Force acting on an accelerating car.

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## Objects in Orbit

Relative mass of weightless objects.

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## Accelerating Pendulum

Finding the period of a pendulum in a moving elevator.

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## Submerged Ball

3-part problem involving balls submerged in liquid; finding displaced mass, apparent weight of liquid container.

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