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

Total Price: R

There are no items in this cart.
Continue Shopping
Get instant 20% OFF on Online Material.
coupon code: MOB20 | View Course list

  • Kinematics & Rotational Motion
  • View Details
Get extra R 120 off


MI  of a  ring is mr^2.

If  we  treat rings as  elements of a disc as well as of a hemisphere,then MI of   a disc and of hemisphere should be  same (becoz mass  as well as perp. distance of  every corresponding ring in both from  the axis will be same , but  actually  not. What is wrong in the concept?

           (here  axis  is the axis passing through centre and perp. to plane in both cases)

6 years ago


Answers : (1)


Dear neeru

it is because of that for same mass and radius surface area of disk and hemisphear is not same

for disk we right =dm = (M/πR2 ) 2πrdr

and for the hemisphear =dm = (M/2πR2) (2πRsinΘ)(RdΘ)

here we should consider that in case of dish ,element area is a area of ring which is  a plane surface

but in case of hemisphear element area is not plane urface it is a curved surface.

Please feel free to post as many doubts on our discussion forum as you can.
If you find any question Difficult to understand - post it here and we will get you
the answer and detailed  solution very  quickly.

 We are all IITians and here to help you in your IIT JEE preparation.

All the best.
Askiitians Experts

6 years ago

Post Your Answer

Other Related Questions on General Physics

What is the the angle between vector( Vector P & Q )
Sourabh Singh 25 days ago
the angle between the two vectors is 150 degrees.
Y MANJUNADH 24 days ago
Can carbon produce photoelectric effect? when use the laser wave 470nm. voltage between anode and cathnode is limited in the range -1 V to 1 V. Thanks~ Could you send the answer to Email:...
Only metals whih has valency of +1 and +2 are suitable for Photoelectric process. As they are in a rapid condition to take electrons to complete its octet. Thus are more eager to show...
Vikas TU 2 months ago
What is the least size of the antennae for radiating wave of wavelength lamda?
The least size of the antennae for radiating wave of wavelength lambda is one-fourth of the wavelength that is, lambda/4 . Hope you understand my solution . ALL THE BEST..
Adarsh 2 months ago
Calculate the efficiency of a reversible heat engine working between the temperture 100°c and 0°c
26.81% we using the formula of efficiency of the reversible process given by carnot we can easily determine the exact efficiency of that system or any temperature
Poosala Vedaprakash 4 months ago
26.81% by using the formula of eficiency of the reversible process given by carnot u can easily determine the exact eficiency of that system
MRIDUL TRIPATHI 6 months ago
basic concept of calorimetry and heat transportation
@ anjali kindly elaborate your ques a little bit , so, that we can help u in a better way . acc to the principle of calorimetry if there is a diffrence between the temp. of two objects and...
Umakant biswal 22 days ago
Which of the 3 forces do not accelerate and why? A) 5 10 12 B) 10 20 30 C) 10 20 40 D) 5 10 15
Sorry, I didn’t understand your question fully. How can we tell just seeing upon magnitudes of the forces without direction. U must provide some direction of forces acting on any object.
Vikas TU 2 months ago
View all Questions »

  • Complete JEE Main/Advanced Course and Test Series
  • OFFERED PRICE: R 15,000
  • View Details
Get extra R 3,000 off

  • Kinematics & Rotational Motion
  • View Details

Get extra R 120 off

More Questions On General Physics

Ask Experts

Have any Question? Ask Experts

Post Question

Answer ‘n’ Earn
Attractive Gift
To Win!!!
Click Here for details