Example 圆■ Draw a picture showing all of the forces Isolate the forces acting on the block Draw a free body diagram Solve Newton's equations for each component F = max Be-mg may BF F mg Physics 121: Lecture 8, Pg 16
Physics 121: Lecture 8, Pg 16 Example... Draw a picture showing all of the forces. Isolate the forces acting on the block. Draw a free body diagram. Solve Newton’s equations for each component. FX = maX FB,F - mg = maY F FB,F mg j i
Example x =max So ax =fx/m=(10 N)/(2 kg)=5 m/s .F-mg = may But ay=0 So FBe =mg N mg The vertical component of the force of the floor on the object (Fbe)is often called the normal Force(M Since ay =0, N=mg in this case Physics 121: Lecture 8, Pg 17
Physics 121: Lecture 8, Pg 17 Example... FX = maX So aX = FX / m = (10 N)/(2 kg) = 5 m/s2 . FB,F - mg = maY But aY = 0 So FB,F = mg. The vertical component of the force of the floor on the object (FB,F ) is often called the Normal Force (N). Since aY = 0 , N = mg in this case. FX N mg j i
Example Recap N=mg Fx Fy/ mg Physics 121: Lecture 8, Pg 18
Physics 121: Lecture 8, Pg 18 Example Recap FX N = mg mg aX = FX / m j i
Tools: Ropes Strings Can be used to pull from a distance Tension ( T at a certain position in a rope is the magnitude of the force acting across a cross section of the rope at that position The force you would feel if you cut the rope and grabbed the ends An action-reaction pair T cut T Physics 121: Lecture 8, Pg 19
Physics 121: Lecture 8, Pg 19 Tools: Ropes & Strings Can be used to pull from a distance. Tension (T) at a certain position in a rope is the magnitude of the force acting across a crosssection of the rope at that position. The force you would feel if you cut the rope and grabbed the ends. An action-reaction pair. cut T T T
Tools: Ropes Strings ■■■ The direction of the force provided by a rope is along the direction of the rope Since ay =0 (box not moving) m T=mg mg Physics 121: Lecture 8, Pg 20
Physics 121: Lecture 8, Pg 20 Tools: Ropes & Strings... The direction of the force provided by a rope is along the direction of the rope: mg T m Since ay = 0 (box not moving), T = mg