Kinetics of Particle Lecture 8: Tuesday, 9/15/15 Today’s Objective Kinetics of rectilinear motion

What is Kinetics? Kinetics is the study of the relations between unbalanced forces and the resulting changes in motion. Solution Methods for kinetics problems: (A) direct application of Newton's second law (called the force-mass-acceleration method), (B) use of work and energy principles, and (C) solution by impulse and momentum methods

What is Mechanics?

A. Application of Newton’s Second Law Newton’s second law equation: F = ma

Units

Equation of Motion Types of problems: Unconstrained motion Rectilinear motion Curvilinear motion

Rectilinear Motion Motion along a straight line

Free Body and Inertia Body Diagrams Problem 3/1 : The 50-kg crate is projected along the floor with an initial speed of 7 m/s at x = 0. The coefficient of kinetic friction is 0.40. Calculate the time required for the crate to come to rest and the corresponding distance x travelled.

Problem 3/35 Given: The nonlinear spring has a tensile force-deflection relationship given by: , where x is in meters and is in newtons. Determine the acceleration of the 6-kg block if it is released from rest at x = 100 mm

Kinetics of Particle – Curvilinear Motion Lecture 9: Thursday, 9/17/15 Today’s Objective Kinetics of Curvilinear motion

Kinetics of a Particle Curvilinear Motion: Normal and Tangential (n-t) coordinates

Curvilinear Motion Curvilinear Motion: 2. Polar (r, 𝜃) coordinates

Problem 3/50 The 4-oz slider has a speed v = 3 ft/s as it passes point A of the smooth guide, which lies in a horizontal plane. Determine the magnitude R of the force which the guide exerts on the slider. Just before it passes point A of the guide As it passes point B.

Problem 3/53 The hollow tube is pivoted about a horizontal axis through point O and is made to rotate in the vertical plane with a constant ccw angular velocity of 3 rad/s. If a 0.2 lb particle is sliding in the tube toward O with a velocity of 4 ft/s relative to the tube when the 𝜃 = 300 is passed, calculate the normal force exerted by the wall of the tube on the particle at this instant.