For a long time, I have believed that most starting physics courses and textbooks do not cover running motion adequately. I find myself this way because so many of the important principles of movement is employed when analyzing the motion of a running body. For example, to calculate the velocity of a ball running down an slope we must use Newton’s second law and the relationship between torque and angular velocity
(I will call this the “Rotational Picture of Motion”); we must decide whether the ball is susceptible to kinetic or static chaffing; and we must relate the velocity 롤대리 of the center of mass to the angular velocity around the center of mass. Also, when there is no sliding, the efficiency of mechanical energy is often applied. This involves finding out how to express the kinetic energy of a system of allergens and how to relate the velocity of the center of mass to the angular velocity around the center of mass. Basically, all of the important ideas are used when resolving physics problems related to running motion.
There’s so much physics in this subject that we will commit four articles to it. The first covers a standard physics problem solution for running without sliding; the second will describe how sliding affects the motion of a running body; the third will describe how the motion of a body running without sliding can be analyzed in terms of mechanical energy efficiency; and the fourth will demonstrate how relatively difficult running motion problems can be sorted fairly easily when the basic principles are carefully applied. Now about the firstly these four articles.
The written text publisher does not accept many standard exact symbols. As a result, I have had to use some rather unusual exact notation in my articles. All the notation is described in the Ezine article “Teaching Rotational Dynamics”.
Problem. A uniform solid sphere rolls down a aircraft inclined at an angle th without sliding. The male body’s mass, radius, and moment of inertia around the center of mass are Michael, Ur, and Icm = 2(MR**2)/5, respectively. (a) What is the sphere’s velocity? (b) What condition must the coefficient of static chaffing satisfy if there is no sliding?
Solution. (a) A sphere is coming in contact with the surface of the slope, which exerts a normal force In and a frictional force f on it. The weight of the sphere has components along the slope (MGsin(th)) and perpendicular to the slope (MGcos(th)). The motion of the sphere is analyzed using an inertial organize system whoever x axis is parallel to and directed down the slope and a ymca axis directed normal to and away from the slope. With the help of a free-body diagram, we have
In his 1951 Farewell Speech to Congress, General Douglas MacArthur notoriously said, “Once war is forced upon us, there is no other alternative than to apply every available way to bring it to a fast end. War’s very object is glory, not prolonged indecision. In war there is no substitute for glory. inch
MacArthur had been laid off by Us president Harry S Truman as general in control of the Us Command in Korea because he freely disagreed with Truman’s strategy of a limited war which hamstrung his efforts for glory.
The best we could achieve in Korea was a stalemate, an unsure armistice which led us as to the we have today, a divided Korea and a maniacal despot in Ellie Jong Il. We never learned from MacArthur’s words, as verified by our ignominious loss in Vietnam and now by our forthcoming defeat in Afghanistan.
The consequences of a defeat in the Mideast would be far greater than losing ‘Nam. As with Korea and Vietnam, the Afghan war will be lost in Wa, D. C.
The Afghan war was “forced upon us” by the 9/11 attacks orchestrated by ing Qaeda and the Taliban in Afghanistan and history may be on the edge of repeating itself not on the field of battle but in the cozy bounds of the White House.
Us president Obama has summoned the Commander of us Forces in Afghanistan General Stanley McChrystal to the executive estate to go into detail critical and dismissive comments the and his aides made of top administration and Afghan officials.
McChrystal is in a situation much like that of MacArthur in Korea. He wants to win the war in Afghanistan but the administration won’t allow him to. He’s issued an abject apology to the us president for his feedback published in Running Stone; he should have resigned. MacArthur apologized to no one; he didn’t believe he was wrong.
Rather than the “limited war” restraints formed by the Truman administration MacArthur faced in Korea, McChrystal faces the contraints of the “rules of engagement” as determined by the Federal government.
As commander-in-chief, Obama has every directly to conduct the war as he sees fit but it would be more respectable, and would save countless lives, if he simply called it gives up today, began pulling out our soldiers, and dismissed from your job McChrystal when he meets with him tomorrow.