Physic problem(2)...Please help

posted by .

A 15 kg, 1 m wide door which has frictionless hinges is closed but unlocked. A 400 g ball hits the exact middle of the door at a velocity of 35 m/s and bounces off elastically, thereby causing the door to slowly swing open. How long in seconds does it take for the door to fully open (rotate 90 degrees)?

  • Physic problem(2)...Please help -

    1.68?

  • Physic problem(2)...Please help -

    no. wrong answer

  • Physic problem(2)...Please help -

    In vector form:
    Δp⃗ =p₂⃗-p₁⃗ =mv₂⃗-mv₁⃗,
    for magnitudes
    Δp =p₂-(-p₁) =mv₂+mv₁= 2mv.
    p=Mu =>
    Mu=2mv
    The speed of the center of the door is
    u=2mv/M=2•0.4•35/15 = 1.37 m/s
    Its angular speed is
    ω=u/r=2u/L =2. •1.87/1 = 3.73 rad/s
    t= φ/ ω =π/3.73 = 0.84 s.

  • pyhsic -

    wrong answer Elena

  • Physic problem(2)...Please help -

    0.43 s

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. physiC

    A uniform door (0.81 m wide and 2.1 m high) weighs 150 N and is hung on two hinges that fasten the long left side of the door to a vertical wall. The hinges are 1.9 m apart. Assume that the lower hinge bears all the weight of the door. …
  2. Physics

    A uniform 22 kg door that is 2.5 m high by 0.80 m wide is hung from two hinges that are 20 cm from the top and 20 cm from the bottom. If each hinge supports half the weight of the door, find the magnitude and direction of the horizontal …
  3. College physics

    A 0.006 00-kg bullet traveling horizontally with a speed of 1.00 x 10^3 m/s enters an 20.1-kg door, imbedding itself 10.9 cm from the side opposite the hinges as in the figure below. The 1.00-m wide door is free to swing on its frictionless …
  4. Physics

    There is a door that is 1.0 m wide and can rotate about a vertical axis without friction. The door’s mass is 15 kg and is free to swing open. Someone fires a 10 g bullet at 400 m/s into the exact center of the door, perpendicular …
  5. Science

    A 15 kg, 1m wide door which has frictionless hinges is closed but unlocked. A 400 g ball hits the exact middle of the door at a velocity of 35 m/s and bounces off elastically, thereby causing the door to slowly swing open. How long …
  6. Physics

    A 15 kg, 1m wide door which has frictionless hinges is closed but unlocked. A 400 g ball hits the exact middle of the door at a velocity of 35 m/s and bounces off elastically, thereby causing the door to slowly swing open. How long …
  7. heeeeeeeeeeeeeelp Physics

    A 15 kg, 1m wide door which has frictionless hinges is closed but unlocked. A 400 g ball hits the exact middle of the door at a velocity of 35 m/s and bounces off elastically, thereby causing the door to slowly swing open. How long …
  8. Physics

    A 15 kg, 1m wide door which has frictionless hinges is closed but unlocked. A 400 g ball hits the exact middle of the door at a velocity of 35 m/s and bounces off elastically, thereby causing the door to slowly swing open. How long …
  9. Physics

    A 15 kg, 1m wide door which has frictionless hinges is closed but unlocked. A 400 g ball hits the exact middle of the door at a velocity of 35 m/s and bounces off elastically, thereby causing the door to slowly swing open. How long …
  10. pyhsic question for count iblis

    PLEASE GIVE THE ANSWER,I ALREADY INPUT TO YOUR FORMULA AND IT IS FALSE... Is your answer 0.57?

More Similar Questions