Physics And Measurement Question 30
Question: A highly rigid cubical block $ A $ of small mass $ M $ and side $ L $ is fixed rigidly onto another cubical block $ B $ of the same dimensions and of low modulus of rigidity $ \eta $ such that the lower face of $ A $ completely covers the upper face of $ B $ . The lower face of $ B $ is rigidly held on a horizontal surface. A small force $ F $ is applied perpendicular to one of the side faces of $ A $ . After the force is withdrawn block $ A $ executes small oscillations. The time period of which is given by
[IIT 1992]
Options:
A) $ 2\pi \sqrt{\frac{M\eta }{L}} $
B) $ 2\pi \sqrt{\frac{L}{M\eta }} $
C) $ 2\pi \sqrt{\frac{ML}{\eta }} $
D) $ 2\pi \sqrt{\frac{M}{\eta L}} $
Show Answer
Answer:
Correct Answer: D
Solution:
By substituting the dimensions of mass [M], length [L] and coefficient of rigidity $ [ M{{L}^{-1}}{{T}^{-2}} ] $ we get $ T=2\pi \sqrt{\frac{M}{\eta L}} $ is the right formula for time period of oscillations
