Question

Problem : Find the spring constant for a spring that stretches 1.4cm when a 638 g weight is attached to it.  How much work is done as the spring extends?

Answer 1

From the Hook's law we know that, F=-kx (where K=constant, x=sretching length and F=Force)

                 Now, given x=1.4cm, m=638g and we know g=981 cm/sec*2

F=mg=638*981=625878 dyne

therefore,                   

                k= -F/x=-625878/1.4 = -447055.71 g/sec.sec

And, total workdone   W=(k.x.x)/2 = -438114.6 watt