A body falls from a height h=200 m (at New Delhi). The ratio of distance travelled in each 2 sec during t=0 to t=6 second of the journey is:
A
1 : 4 : 9
B
1 : 2 : 4
C
1 : 3 : 5
D
1 : 2 : 3
Step-by-Step Solution
Analyze the Motion: The body falls from rest (u=0) under constant acceleration due to gravity (a=g). The problem asks for the ratio of distances covered in successive equal time intervals of τ=2 s.
Galileo's Law of Odd Numbers: For a body falling from rest, the distances traversed during equal intervals of time stand to one another in the same ratio as the odd numbers beginning with unity .
Ratio = 1:3:5:7:…
Verification via Calculation:
Distance in 1st interval (0−2 s): h1=21g(2)2=2g.
Distance in 2nd interval (2−4 s): Total distance in 4 s (8g) minus distance in 2 s (2g) = 6g.
Distance in 3rd interval (4−6 s): Total distance in 6 s (18g) minus distance in 4 s (8g) = 10g.
Ratio: 2g:6g:10g=1:3:5.
Check Validity: The total distance fallen in 6 s is approximately 180 m (taking g=10 m/s2), which is less than the initial height of 200 m, so the body is still in flight.
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