Fizik 2 demensi

The Acceleration of Objects by Forces at AnglesSeveral of the problems in this set target your ability to analyze objects which are moving across horizontal surfaces and acted upon by forces directed at angles to the horizontal. Previously, Newton's second law has been applied to analyze objects accelerated across horizontal surfaces by horizontal forces. When the applied force is at an angle to the horizontal, the approach is very similar. The first task involves the construction of a free-body diagram and the resolution of the angled force into horizontal and vertical components. Once done, the problem becomes like the usual Newton's second law problem in which all forces are directed either horizontally or vertically.
The free-body diagram above shows the presence of a friction force. This force may or may not be present in the problems you solve. If present, its value is related to the normal force and the coefficient of friction (seeabove). There is a slight complication related to the normal force. As always, an object which is not accelerating in the vertical direction must be experiencing a balance of all vertical forces. Thatis, the sum of all up forces is equal to the sum of all down forces. But now there are two up forces -the normal force and the Fyforce (vertical component of the applied force) As such, the normal force plus the vertical component of the applied force is equal to the downward gravity force. That is,Fnorm+ Fy= FgravThere are other instances in which the applied force is exerted at an angle below the horizontal. Once resolved into its components, there are two downward forces acting upon the object - the gravity force and the vertical component of the applied force (Fy). In such instances, the gravity force plus the vertical component of the applied force is equal to the upward normal force. That is,Fnorm= Fgrav+ FyAs always, the net force is the vector sum of all the forces. In this case, the vertical forces sum tozero; the remaining horizontal forces will sum together to equal the net force. Since the friction force is leftward (in the negative direction), the vector sum equation can be written asFnet= Fx- Ffrict= m • aThe general strategy for solving these problems involves first using trigonometric functions to determine the components of the applied force. Iffriction is present, a vertical force analysis is used to determine the normal force; and the normal force is used to determine the friction force. Then the net force can be computed using the above equation. Finally, the acceleration can be found using Newton's second law of motion.

ilibriumSeveral of the problems in this set target your ability to analyze objects which are suspended atequilibrium by two or more wires, cables, or strings. In each problem, the object is attached by a wire, cable or string which makes an angle to the horizontal. As such, there are two or more tension forces which have both a horizontal and a vertical components. The horizontal and vertical components of these tension forces is related to the angle and the tension force value by a trigonometric function (see above). Since the object is at equilibrium, the vector sum of all horizontal force components must add to zero and the vector sum of all vertical force components must add to zero. In the case of the vertical analysis, there is typically one downward force - the force of gravity - which is related to themass of the object. There are two or more upward force components which are the result ofthe tension forces. The sum of these upward force components is equal to the downward force of gravity.The unknown quantity to be solved for could be the tension, the weight or the mass of the object; the angle is usually known. The graphic above illustrates the relationship between these quantities.