A spring has a natural length of 20 cm. If a force of 25 N is required to keep it stretched to a length of 30 cm, how much work is required to stretch it from 20 cm to 32 cm?
A) $1.80 \mathrm{~J}$
B) $3.80 \mathrm{~J}$
C) $5.80 \mathrm{~J}$
D) $4.80 \mathrm{~J}$
E) $2.80 \mathrm{~J}$

Question

Quizplus · Accepted Answer

The work done in stretching the spring from 20 cm to 32 cm is equal to the area under the force-displacement graph. The force-displacement graph is a straight line, so the area under the graph is a triangle with a base of 12 cm and a height of 25 N. Therefore, the work done is:$$W = \frac{1}{2} 	imes 12 \mathrm{~cm} 	imes 25 \mathrm{~N} = 150 \mathrm{~cm-N} = 1.5 \mathrm{~J}$$

A Spring Has a Natural Length of 20 Cm 1.80 J1.80 \mathrm{~J}1.80 J

A Spring Has a Natural Length of 20 Cm $1.80 \mathrm{~J}$