sy17_oct31_07hc

# sy17_oct31_07hc - Physics 207 Lecture 17 Pg 1 Physics 207...

This preview shows pages 1–9. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Physics 207: Lecture 17, Pg 1 Physics 207, Physics 207, Lecture 17, Oct. 31 Lecture 17, Oct. 31 Agenda: Agenda: ● Review for exam Review for exam ● Exam will be held in rooms B102 & Exam will be held in rooms B102 & B130 in Van Vleck at 7:15 PM Assignment: Assignment: ● MP Homework 7, Ch. 11, 5 problems, MP Homework 7, Ch. 11, 5 problems, NOTE: Due Wednesday at 4 PM NOTE: Due Wednesday at 4 PM ● MP Homework 7A, Ch. 13, 4 problems, available today MP Homework 7A, Ch. 13, 4 problems, available today Physics 207: Lecture 17, Pg 2 Example Example Gravity, Normal Forces etc. Gravity, Normal Forces etc. Consider a women on a swing: When is the tension on the rope largest ? And is it : (A) greater than (B) the same as (C) less than the force due to gravity acting on the woman Physics 207: Lecture 17, Pg 3 Gravity, Normal Forces etc. Gravity, Normal Forces etc. At the bottom of the swings and is it (A) greater than the force due to gravity acting on the woman v m g T F c = m a c = m v 2 / r = T- mg T = mg + m v 2 / r m g T F c = m 2 / r = 0 = T – mg cos θ F T = m aT = mg sin θ θ Physics 207: Lecture 17, Pg 4 Newton’s Laws Newton’s Laws Three blocks are connected on the table as shown. The table has a coefficient of kinetic friction of 0.350, the masses are m 1 = 4.00 kg, m 2 = 1.00kg and m 3 = 2.00kg. a) What is the magnitude and direction of acceleration on the three blocks ? b) What is the tension in the two cords ? m 1 T 1 m 2 m 3 Physics 207: Lecture 17, Pg 5 Problem Problem Three blocks are connected on the table as shown. The table has a coefficient of kinetic friction of μ K =0.40 , the masses are m 1 = 4.0 kg, m 2 = 1.0 kg and m 3 = 2.0 kg. (A) FBD (except for friction) (B) So what about friction ? m 1 T 1 m 2 m 3 m 2 g N m 3 g m 1 g T 3 T 1 Physics 207: Lecture 17, Pg 6 Problem recast as 1D motion Problem recast as 1D motion Three blocks are connected on the table as shown. The center table has a coefficient of kinetic friction of μ K =0.40 , the masses are m 1 = 4.0 kg, m 2 = 1.0 kg and m 3 = 2.0 kg. m 1 m 2 m 3 m 2 g N m 3 g m 1 g T 3 T 1 frictionless frictionless m 1 g > m 3 g and m 1 g > ( μ k m 2 g + m 3 g) and friction opposes motion (starting with v = 0) so f f is to the right and a is to the left (negative) f f Physics 207: Lecture 17, Pg 7 Problem recast as 1D motion Problem recast as 1D motion Three blocks are connected on the table as shown. The center table has a coefficient of kinetic friction of μ K =0.40 , the masses are m 1 = 4.0 kg, m 2 = 1.0 kg and m 3 = 2.0 kg. m 1 m 2 m 3 m 2 g N m 3 g m 1 g T 3 T 1 frictionless frictionless x-dir: 1. Σ F x = m 2 a = μ k m 2 g - T 1 + T 3 m 3 a = m 3 g - T 3 m 1 a = - m 1 g + T 1 Add all three: ( m 1 + m 2 + m 3 ) a = μ k m 2 g + m 3 g – m 1 g f f T 3 T 1 Physics 207: Lecture 17, Pg 8 Lecture 17, Lecture 17, Exercise Exercise Work/Energy for Non-Conservative Forces Work/Energy for Non-Conservative Forces A. 2.5 J B. 5.0 J C. 10. J D.-2.5 J E.-5.0 J F.-10. J 1 m e t e...
View Full Document

{[ snackBarMessage ]}

### Page1 / 47

sy17_oct31_07hc - Physics 207 Lecture 17 Pg 1 Physics 207...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online