- #1
IWillBarelyUseThis
- 3
- 1
- Homework Statement
- Don't have exact wording, but the basics are this: A man steals a purse and runs across the field at 5.5m/s. A nearby woman sees this, and while the man passes her, she begins accelerating at 2.5m/(s^2) after him. She reaches her maximum speed of 7.0m/s as she catches the robber. What is her displacement from where she started?
It was multiple choice, and though I don't remember all the answers, I remember that 36m was the correct one, and that my answer of 9.8m was not an option.
- Relevant Equations
- The equations that I tried led to an answer that wasn't an option, and the teacher said it was entirely wrong, but it was essentially (final velocity squared - initial velocity squared) / (2 × acceleration) = displacement. Basic rearranging of an equation on the formula sheet.
So the equation I had used made sense to me because through the wording of the question, since we have an initial velocity of 0m/s, and an acceleration of 2.5m/(s^2), and it was implied in the question that she caught the robber at the exact same time as she reached her maximum velocity, and therefore also final velocity. I plugged the values into the equation, given to us on a formula sheet, and solved for displacement, which was 9.8m. Of course, that wasn't one of the answers, and her explanation made no sense. Along with that- she also said that her explanation would NOT make sense to us unless we were in her physics 20 class last semester. Now, I took that class last year, meaning I didn't have her as a teacher, and don't understand what her explanation was, but that's a lazy excuse to explain why your students don't know what you're doing. It means you aren't teaching them properly for starters, and more importantly, neither of the other two people in my group knew what she was talking about either. (And both of them were in the class last semester). So, assuming my answer is incorrect, and the question ISN'T worded as poorly as I think it is, how would I go about finding this value of 36m?