Question

When a long spring is stretched by 2 cm, its potential energy is V. If the spring is stretched by 10 cm, the potential energy in it will be:

• A. 10 V
• B. 25 V
• C. $\frac { V } { 5 }$
• D. 5 V

Answer 1

Answer: (B)

25 V

Answer 2

Potential energy in a stretched spring is given by $\mathrm { v } = \frac { 1 } { 2 } \mathrm { kx } ^ { 2 }$

$\therefore \frac { \mathrm { v } _ { 1 } } { \mathrm { v } _ { 2 } } = \left( \frac { \mathrm { x } _ { 1 } } { \mathrm { x } _ { 2 } } \right) \quad \therefore \frac { \mathrm { v } _ { 1 } } { \mathrm { v } _ { 2 } } = \left( \frac { 0.02 } { 0.1 } \right) = \frac { 1 } { 25 }$