Thank you for registering.

One of our academic counsellors will contact you within 1 working day.

Please check your email for login details.
MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: Rs.

There are no items in this cart.
Continue Shopping

in the figure two identical rods OA and OB each of length l and mass m are connected to each other by a massless pin connection(both the rods can rotate about the pin o which is free to move), that allowsfree rotation. The assembly is kept on a frictionless horizontal plane. Now two point masses each of mass m moving with speed u perpendicular to the AB and hit the assembly inellastically at points A and B as shown. q : find the angular speed of the rods just after the collision A)3u/4l B)6u/5l C) 3u/2l D)none of these key (B)


in the figure two identical rods OA and OB each of length l and mass m are connected to each other by a massless pin connection(both the rods can rotate about the pin o which is free to move), that allowsfree rotation. The assembly is kept on a frictionless horizontal plane. Now two point masses each of mass m moving  with speed u perpendicular to the AB and hit the assembly inellastically at points A and B as shown.


q : find the angular speed of the rods just after the collision


A)3u/4l B)6u/5l  C) 3u/2l D)none of these


key (B)



704_17851_q.GIF

Grade:

2 Answers

vikas askiitian expert
509 Points
10 years ago

moment of inertia of rod about point  O is IR = mL2/3 

moment of inertia of particle about O is Ip = mL2

total moment of inertia of ststem = 2IR + 2Im

                                        I = 8mL2/3          ..............1

now , since no external torque is acting on the system so angular momentam will remain conserved ,

Li = Lf     .........2

Li = muL + muL = 2muL           (sum of angular momentam of indivisual particles)

finally let this system ( rod + 2 masses) is rotating with W angular velocity then

Lf = IW 

putting these values in eq 2 we get

W = 2muL/I =  3u/4L

this is the required ans

SAGAR SINGH - IIT DELHI
879 Points
10 years ago

Dear student,

Its a simple problem, just apply principle of conservation of angular momentum about point O and you will get the result..

Please feel free to ask your queries here. We are all IITians and here to help you in your IIT JEE preparation.

All the best.

Win exciting gifts by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian.

Now you score 5+15 POINTS by uploading your Pic and Downloading the Askiitians Toolbar  respectively : Click here to download the toolbar..

 

Askiitians Expert

Sagar Singh

B.Tech, IIT Delhi

Think You Can Provide A Better Answer ?

Provide a better Answer & Earn Cool Goodies See our forum point policy

ASK QUESTION

Get your questions answered by the expert for free