ملتقى الفيزيائيين العرب

ملتقى الفيزيائيين العرب (http://www.phys4arab.net/vb/index.php)
-   فيزياء المرحلة الجامعية. (http://www.phys4arab.net/vb/forumdisplay.php?f=14)
-   -   هل من مجيب قبل الساعة الثالثة بتوقيت مكة المكرمة (http://www.phys4arab.net/vb/showthread.php?t=29773)

s.a.l.m.a.n 30-11-2008 13:05

هل من مجيب قبل الساعة الثالثة بتوقيت مكة المكرمة
 
بسم الله الرحمن الرحيم

السلام عليكم ورحمة الله وبركاته

Mamentum and impulse



1) When a ball is hit with a given force , why does contact over a long time impart more speed to the ball??



2) Which undergoes the greatest change in momentum :



A) a baseball that is caught

B) a baseball that is thrown or

c) a baseball that is caught and then thrown back ,

if all of the baseballs have the same speed just befor being caught and just after being thrown



3) Railroad car A rolls at a certain speed and makes aperfectly elastic collision with car B of the same mass .After the collision . car A is observed to be at rest . How does the speed of car B compare with the initial speed of car A ?



4) To bring a supertanker to a stop , its engines are typicaaly cut off about 25 Km from port . Why is it so diffcult to stop or turn a supertanker??



5) In terms of impules and momentum , why do airbags in cars reduce chances of injury in accidets?



6) Your Friend says that he law of momentum conservation is violated when a ball rolls down a hill and gains momentum . What do you say??

Obama08 03-12-2008 00:52

رد: هل من مجيب قبل الساعة الثالثة بتوقيت مكة المكرمة
 
[align=left]بسم الله الرحمن الرحيم

1.when the ball contact over along time, more impulse will be generated ;
Implulse = force*Time , since impulse = change in momentum
the momentum is getting bigger and then impart more speed to the ball

2. the greatest change in momentum in C

3. in a perfectly elastic collision apply conservation of momentum and conservation of energy (kinetic).[/align]



[align=center]:fantastic_new:[/align]


الساعة الآن 22:04

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd. TranZ By Almuhajir