Question

A spring when stretched by 2 mm its potential energy becomes 4 J. If it is stretched by 10 mm, its potential energy is equal to

• A. 4 J
• B. 54 J
• C. 415 J
• D. None

Answer 1

Answer: (D)

None

Answer 2

$U = \frac { 1 } { 2 } k x ^ { 2 }$ if x becomes 5 times then energy will become 25 times i.e.