1. a star is observed from two diametrically opposite points P & Q on earth , the angle 'x' subtended at the star by the two directions of observations is 1 degree 54 minutes . given the radius of earth 0.638x10 raised to 7.compute the distance of the star from earth . 2. by using dimensional analysis derive an expression for time period off a pendulum.

Asked by Subiya Khan | 11th Oct, 2013, 11:21: AM

Expert Answer:

1) We have
? = 1°54' = 114' = 114 × 60" × 4.85 × 10-6 rad = 3.32 × 10-2 rad
 
The distance D of star from earth is D = d/?
Here, d is diameter of earth = 1.276 × 107 m
 
Thus, we have
 
 
2) Let us say that time period depends on l, g and m as
 
T = k lx gy mz
 
Consider dimensions of both sides of above equation
 
k is not found by dimensions. We have, K = 2 ?

Answered by Romal Bhansali | 11th Oct, 2013, 01:19: PM

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