Question

A spring with spring constant k when stretched through 1 cm, the potential energy is U. If it is stretched by 4 cm. The potential energy will be

• A. 4U
• B. 8U
• C. 16 U
• D. 2U

Answer 1

Answer: (C)

16 U

Answer 2

Potential energy $U = \frac { 1 } { 2 } k x ^ { 2 }$

∴$U \propto x ^ { 2 }$[if k = constant]

If elongation made 4 times then potential energy will become 16 times.