A spring of spring constant `5 xx 10^(3) N//m` is stretched initially by 5 cm from the unstretched position. The work required to further stretch the spring by another 5 cm is .

Options

A. `6.25 N-m`
B. `12.50 N-m`
C. `18.75 N-m`
D. `25.00 N-m`

Answer

C

Explanation

Here, `W = (1)/(2) k(x_(2)^(2) - x_(1)^(2))`
=`(1)/(2) xx 5 xx 10^(3) [((10)/(100))^(2) -((5)/(100))^(2)]`
=`(1)/(2) x (5 xx10^(3))/(10^(4))[100-125] = (75)/(4)`
`18.75 J`.