A block is hanging on a spring. The length of the Spring is a linear function of the mass of the block. What is the length of the spring in cm when an 11 gram block is suspended from it?
(a)31
(b)36
(c)39
(d)41
(e)45

Question

A block is hanging on a spring. The length of the Spring is a linear function of the mass of the block. What is the length of the spring in cm when an 11 gram block is suspended from it? 
(a)31
(b)36
(c)39
(d)41
(e)45

anonymous · Answer

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zpupster · Answer

We are required to find the length of spring when a block of 11 grams is suspended from it...
 According to given conditions the spring increases its length from 27 cm to 35 cm as Mass is increased from 5 grams to 9 grams. As the increase is of 4 grams ( 9 grams - 5 grams = 4 grams ) then we will have to find out the difference of the increased length i.e 35 - 27 = 8.
 Now we come to know that for every 4 grams there is an increase of 8 centimeters.
 Now the final condition is 15 grams due to which there is an increase in spring up to 47 centimeter.
 All we need to do is subtract 4 grams from the final condition that will make our required statement i.e to know about the length if mass is 11 grams, and we will subtract 8 centimeters from 47 centimeters which makes 39.