A spring when stretched by 2 mm its potential energy becomes 4J. If it is stretched by 6 mm its potential energy becomes.

Question

A spring when stretched by 2 mm its potential energy becomes 4J. If it is stretched by 6 mm its potential energy becomes. (A) 32 J (B) 36 J (C) 30 J (D) 40 J

Tardigrade Admin · Accepted Answer

u=(1/2) k x2 ⇒ u propto x2 ⇒ (u1/u2)=((2/6))2 ∴ u2=u1 × (36/6)=4 × 9=36 J

Q. A spring when stretched by $2 mm$ its potential energy becomes $4 J$ . If it is stretched by $6 mm$ its potential energy becomes.

$32 J$

$36 J$

$30 J$

$40 J$

$u = \frac{1}{2} k x^{2}$
$\Rightarrow u \propto x^{2}$
$\Rightarrow \frac{u _{1}}{u _{2}} = (\frac{2}{6})^{2}$
$∴ u_{2} = u_{1} \times \frac{36}{6} = 4 \times 9 = 36 J$

Q. A spring when stretched by 2mm its potential energy becomes 4J. If it is stretched by 6mm its potential energy becomes.

32J

36J

30J

40J