Phys298Exam1Sp08-Solutions - Phys 298 Brown Friday February...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Phys 298 Brown Exam 1 Name ______________________________ Friday, February 8, 2008 This is a closed-book, closed-note, closed-neighbor exam. You are allowed one 3”x5” card with information, a calculator (not a computer), and your writing instruments. Multiple choice questions each have only one correct choice. Partial credit will be given on the ‘work-out’ problems. You may use the value g = 10 m/s 2 where needed. Good luck, and “May the Net Force be with you!” 1. An eccentric Physics professor sits in an airplane holding an unwound yo-yo such that it hangs straight down. As the plane accelerates down the runway toward take-off, the professor notices that the yo-yo string makes an angle θ with the vertical. What is the acceleration of the airplane? (Yes, I really did this once, traveling with a student to a research conference). a. g cos " b. g sin " c. g tan " d. g e. 0 F x = T sin " = ma F y = T cos " # mg = 0 $ T cos " = mg % % T sin " T cos " = ma mg $ a = g tan " 2. An object is moving a. There is a net force on the object in the direction of motion. b. There is a net force on the object in the direction opposite motion. c. No forces act on the object. d. Not enough information is given to comment on forces on the object. 3. An object is initially moving in the positive x-direction with speed v 0 . It is acted on for a time t by a net force in the negative y-direction. At the end of this time, what is the x-component of velocity? First, a moving object doesn’t HAVE to have a force acting on it – that’s an old Aristotelian idea. Second, we don’t know HOW the object is moving. A force in the y-direction doesn’t affect motion in the x-direction.
Image of page 1

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

View Full Document Right Arrow Icon
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern