AN ABJECT IS DROPPED FROM REST AT A HEIGHT OF 150 M AND SIMULTANEOUSLY ANOTHER OBJECT IS DROPPED FROM REST AT A HEIGHT OF 100 M.WHAT IS THE DIFFERENCE IN THEIR HEIGHTS AFTER 2 SECONDS,IF BOTH THE OBJECTS DROP WITH SAME ACCELERATIONS? HOW DOES THE DIFFERENCE IN HEIGHTS VARY WITH TIME?

Asked by vrishti TOKAS | 19th Jul, 2015, 09:33: AM

Expert Answer:

The two objects fall with same acceleration simultaneously. Hence, after 2 seconds the difference in their heights will still be 50 m.
 
begin mathsize 12px style straight d subscript 1 equals straight h subscript 1 minus straight s subscript 1 straight d subscript 1 equals 150 minus 1 half at squared equals 150 minus open parentheses 1 half cross times 10 cross times 4 close parentheses straight d subscript 1 equals 150 minus 20 equals 130 space straight m end style
 
Hence, the height of first object after 2 seconds is 130 m.
 
Similarly the height of second object is
 
begin mathsize 12px style straight d subscript 2 equals straight h subscript 2 minus straight s subscript 2 straight d subscript 2 equals 100 minus 1 half at squared equals 100 minus open parentheses 1 half cross times 10 cross times 4 close parentheses straight d subscript 1 equals 100 minus 20 equals 80 space straight m end style
 
Hence, the height of second object after 2 seconds is 80 m.
 
So, the difference is same, i.e. 50 m.
 
Hence, we can conclude that the difference in height of the two objects does not depend on time and will always be same.

Answered by Faiza Lambe | 19th Jul, 2015, 11:53: AM

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