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QNEET-2023-Ph-232: NEET 2023 Physics - Class 11 NEET-2023-Ph-232 Solution: The potential energy of a long spring when stretched by 2 cm is …
The potential energy of a long spring when stretched by 2 cm is U. If the spring is stretched by 8 cm potential energy stored in it will be: 4U 8U 16U 2U
Multiple Choice Options
- A 4U
- B 8U
- C 16U
- D 2U
Step-by-Step Verified Solution
The potential energy (U) stored in a spring when it is stretched or compressed is given by the formula:
U = 1 2 k x 2
where:
k is the spring constant,
x is the displacement from the spring's equilibrium position (i.e., how much the spring is stretched or compressed).
If the spring is initially stretched by 2 cm (or 0.02 meters, since we generally use SI units for these calculations), the potential energy stored can be represented as:
U = 1 2 k ( 0.02 ) 2
When the spring is stretched by 8 cm (or 0.08 meters), the new potential energy U _ becomes:
U _ = 1 2 k ( 0.08 ) 2
To find the relation between U _ and U , we can divide the expression for U _ by that of U :
U _ U = 1 2 k ( 0.08 ) 2 1 2 k ( 0.02 ) 2
Simplifying this quotient gives:
U _ U = ( 0.08 0.02 ) 2 = ( 4 ) 2 = 16
Thus, if the spring's displacement is increased from 2 cm to 8 cm, the potential energy stored in the spring increases by a factor of 16 , meaning:
U _ = 16 U