Tsepiso Posted July 18, 2015 Report Share Posted July 18, 2015 (edited) Hi guys, I need help with this question: The acceleration of a car is 1/40(60-v)ms-2, when its velocity is vms-1 . Given that the car starts from rest, find the velocity of the car after 30 seconds (6 marks). Edited July 20, 2015 by Tsepiso Reply Link to post Share on other sites More sharing options...
kw0573 Posted July 18, 2015 Report Share Posted July 18, 2015 (edited) EDIT:I am not allowed to offer solutions to IA questions. So please clarify that this is not an IA question because it doesn't seem like it. Please remove the IA label if applicable. The question involves differential equations that's all I'm going to say for now. I can show you a solution after I know for sure this is not IA. Edited July 18, 2015 by kw0573 Reply Link to post Share on other sites More sharing options...
Tsepiso Posted July 20, 2015 Author Report Share Posted July 20, 2015 EDIT:I am not allowed to offer solutions to IA questions. So please clarify that this is not an IA question because it doesn't seem like it. Please remove the IA label if applicable. The question involves differential equations that's all I'm going to say for now. I can show you a solution after I know for sure this is not IA. I'm sorry, I didn't realise, it was a mistake, its a question from a past paper, paper 2, thanks 1 Reply Link to post Share on other sites More sharing options...
kw0573 Posted July 20, 2015 Report Share Posted July 20, 2015 I would assume you are taking Calculus Option for Paper 3. If you are not doing the Calculus Option then rest assured that this won't be on your exam. The differential equation has since been taken out of core. Assuming v is velocity, a is acceleration. v(t), and a(t) are the respective functions in terms of time.Givens: We have to remember that acceleration can be velocity-based (with respect to change in velocity, as it in the question), displacement-based, or time-based. When the question mentions time, it's likely we need to convert it to or from time-based. To do so we need a differential equation.So we have a separable (typical) differential equation and we are looking to solve for vIntegrate both sides with respect to change in time. So continue solve for v in terms of t. Solve for the C constant with given v(0) = 0. Once you get the expression for velocity in terms of time you sub in t = 30 to get the answer. 1 Reply Link to post Share on other sites More sharing options...
Tsepiso Posted July 21, 2015 Author Report Share Posted July 21, 2015 Awwwww! Thanks, ahhh, I'm doing the Sets option, so thanks a loooottt! I get it though. 1 Reply Link to post Share on other sites More sharing options...
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