Swinburne University of Technology Faculty of Science, Engineering & Technology PHY20008 - Physics 2B Classical Mechanics - Lecture Workbook (Week 2) Class 5: Work and Energy "ACTUM PER.LITTERAS 1) 1 0 00, 00, 0 0 (=2 +199) (a) Calculate the work done moving from A to B along the red path shown. (b) Calculate the work done moving from A to B along the blue path shown. 2)!0( 0 00, 0), 0 0( ={2 []) Calculate the work done using the same two paths as in question 1 above. 3) Calculate the curl of the two forces in questions 1 and 2. PHY20008-Physics 2B Classical Mechanics Lecture Workbook 1
Class 6: Conservation of Energy 0 1) Calculate the components of the curl of an inverse square force; 'x 2) Consider the Hooke's Law force ' D I = 2 0 10), where x is the particle location relative to some reference point, and x, is the position where the force goes to zero. (a) Find the expression for the change in potential energy as the particle moves between locations X1 and x2. (b) From (a), find an expression for the potential energy at any location, x. (c) What does the expression in (b) become if the reference location is chosen as x0? PHY20008-Physics 2B Classical Mechanics Lecture Workbook 2
Class 6: Conservation of Energy (cont.) 3) The potential energy for the gravitation force and the electrostatic force ("Coulomb" force) are similar 1 0 ?- ), since they are both inverse square laws. However, they have a different signs; gravity has 3GmM, and electrostatic has +kQq. Briefly explain the reason(s) for this difference in sign. 4) Calculate the escape velocity of the earth. 00 øøøøø = 6.37×10" !! m lløøøøø = 5.97×10"ª !! kg 10 = 6.674x10000 !! Nm2/kg2 PHY20008-Physics 2B Classical Mechanics Lecture Workbook 3