Author Topic: M1 question  (Read 702 times)

Offline missbeautiful789

  • SF Immigrant
  • **
  • Posts: 55
  • Reputation: 1008
  • Gender: Male
  • Tala al Badru
M1 question
« on: March 27, 2010, 04:29:23 pm »
A box of weight W rests on a platform. When the platform is moving upwards with an of acceleration ?, the normal contact force from the platform on the box has magnitude kW. When the platform is moving downwards with acceleration 2?, the box remains in contact with it. find the normal contact force in terms of k and W, deduce that k ? 3/2
Allâhumma innî a‘ûdhu bika min al-hammi wa al-hazan. Wa a‘ûdhu bika min al-‘ajzi wa al-kasal.

Wa a‘ûdhu bika min al-jubni wa al-bukhl. Wa a‘ûdhu bika min ghalabat id-dayni wa qahr ir-rijal.

{Oh Allah, I seek refuge in You from worry and grief, from helplessness and laziness, from cowardice an

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: M1 question
« Reply #1 on: March 27, 2010, 05:46:02 pm »
2 hours

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: M1 question
« Reply #2 on: March 27, 2010, 07:03:06 pm »
moving up res kW-W=Wa/g (1)
moving down W=W*2a/g so a=g/2
sub into (1) kW-W=W/2 so KW=3W/2 so k=3/2