Allemande135 Posted March 30, 2019 Report Share Posted March 30, 2019 I am really stuck on how to solve these questions and I don't understand why the mark scheme says that the answers for question 8, 12 and 14 are A, A and D, respectively. I would greatly appreciate any help/suggestions/tips!! These questions are from the Paper 1 in May 2018 Timezone 2. Reply Link to post Share on other sites More sharing options...
kw0573 Posted March 30, 2019 Report Share Posted March 30, 2019 14. Let t be the time for the slower wave takes to reach detector; the faster wave takes t - 15 5(t) = 7.5(t - 15) (distance traveled by both waves is the same). t = 45 5 km/s * 45 s = 225 km 12. Temperature and internal energy are related to average kinetic energy of the molecules (that is, kinetic energy with respect to center of mass). Since only the center of mass is moving, and we are not shaking the container, there is no change in temperature and no change in internal energy. 8. The net force of system = total mass of system * net acceleration Net force is the weight, W. Total mass is M and the mass of the weight, or W/g, and net acceleration is a. W = (M + W / g) * a W (1 - a/g) = Ma W = Ma / (g/g - a/g) W = Mag / (g - a) 1 Reply Link to post Share on other sites More sharing options...
Reyanish Posted May 27, 2021 Report Share Posted May 27, 2021 On 3/30/2019 at 11:17 AM, kw0573 said: 14. Let t be the time for the slower wave takes to reach detector; the faster wave takes t - 15 5(t) = 7.5(t - 15) (distance traveled by both waves is the same). t = 45 5 km/s * 45 s = 225 km 12. Temperature and internal energy are related to average kinetic energy of the molecules (that is, kinetic energy with respect to center of mass). Since only the center of mass is moving, and we are not shaking the container, there is no change in temperature and no change in internal energy. 8. The net force of system = total mass of system * net acceleration Net force is the weight, W. Total mass is M and the mass of the weight, or W/g, and net acceleration is a. W = (M + W / g) * a W (1 - a/g) = Ma W = Ma / (g/g - a/g) W = Mag / (g - a) I have the same question but regarding to question 8. I saw your answers and they're great! There's just something that I can't understand in question 8; how do we solve for W? I am struggling to understand how we get Mag at the top and why we have to g's. If possible, can you show how to solve for W? I would really appreciate it, I can't find the answer. Reply Link to post Share on other sites More sharing options...
IBsciencewhiz Posted December 1, 2021 Report Share Posted December 1, 2021 If anyone else is struggling with not having worked solutions to multiple choice answers in IB physics revision take a look at https://tibertutor.com They have insane resources for IB Biology and Chemistry and are going to add physics questions soon which will have worked solutions for all of their questions! Reply Link to post Share on other sites More sharing options...
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