Physics 121, Sections 9, 10, 11, and 12 Lecture 8 Today's Topics Homework 3: Due Friday Sept 23@ 6: 00PM Ch.3:#64,75,and81 Ch4:#4,8,21,25,36,40,and51 Chapter 4: Motion in 2-D More examples of FBD's Examples with friction Physics 121: Lecture 8, Pg 1
Physics 121: Lecture 8, Pg 1 Physics 121, Sections 9, 10, 11, and 12 Lecture 8 Today’s Topics: Homework 3: Due Friday Sept. 23 @ 6:00PM Ch.3: # 64, 75, and 81. Ch.4: # 4, 8, 21, 25, 36, 40, and 51. Chapter 4: Motion in 2-D More examples of FBD’s Examples with friction
An Example Consider the following two cases Physics 121: Lecture 8, Pg 2
Physics 121: Lecture 8, Pg 2 An Example Consider the following two cases
An Example The Free Body Diagrams mg FBT N mg Ball falls For static Situation mg Physics 121: Lecture 8, Pg 3
Physics 121: Lecture 8, Pg 3 An Example The Free Body Diagrams mg mg FB,T= N Ball Falls For Static Situation N = mg
An Example The action/reaction pair forces B,E"-mg F BT N B.EF-mg EB=mg EB= mg Physics 121: Lecture 8, Pg 4
Physics 121: Lecture 8, Pg 4 An Example The action/reaction pair forces FB,E = -mg FB,T= N FE,B = mg FB,E = -mg FE,B = mg FT,B= -N
Lecture 8. ACT 1 Gravity and Normal Forces a woman in an elevator is accelerating upwards The normal force exerted by the elevator on the woman is A) greater than B)the same as C)less than the force due to gravity acting on the woman Physics 121: Lecture 8, Pg 5
Physics 121: Lecture 8, Pg 5 Lecture 8, ACT 1 Gravity and Normal Forces A woman in an elevator is accelerating upwards The normal force exerted by the elevator on the woman is, A) greater than B) the same as C) less than the force due to gravity acting on the woman