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] = 1/2xx (5 xx 10^3)/(10^4) [100 - 25] = 75/4 = 18.75 J`.