Question

the length of a string is 16cm.Its length becomes 20cm when supporting a weight of 5N.Calculate the length of the string when supporting a weight of 6N.Comment on the answer​

Answer 1

`20.8cm`

Step-by-step explanation:

According to hooks law "provide the elastic limit of an elastic material is not exceeded the extension e is directly proportional to the applied force F"

`F= ke`

where F= applied force

k= spring constant

e= extension

Given data

length of string l = 16cm

extension e = 20-16= 4cm

applied force = 5N

we need t o first calculate the spring constant k

apply the formula

`F= ke`

`5=k*4\\k= (5)/(4) \\k= 1.25N/cm`

we can now calculate the extension of the string when supporting a 6N weight

`F= ke\\6=1.25*e\\e= (6)/(1.25) \\e= 4.8cm`

The length of the string when supporting a 6N weight is

`= length+ extension\\= 16+4.8\\= 20.8cm`

COMMENT :According to the analysis an extra weight of 1N will cause add 0.8cm to the length of the string