A-light-wire-which-obeys-hooke-s-law-hangs-vertically-on-a-fixed-support-The-wire-has-an-unstretched-lenght-of-15cm-The-lenght-of-the-wire-however-increase-to-20cm-when-a-load-of-0-5kg-is-attached-

Question Number 13727 by tawa tawa last updated on 22/May/17

A light wire which obeys {hooke}^{'} s law hangs vertically on a fixed support .

The wire has an unstretched lenght of 15 cm . The lenght of the wire however

increase to 20 cm when a load of 0 . 5 kg is attached to it lower end . What is the

tension in the wire when the load is at rest ? .

If the load is pulled down until the lenght of the wire is 22 cm . What is the new

tension in the wire (g = 9.8 m / s) .

Commented by tawa tawa last updated on 23/May/17

please help . Thanks in advance .

Answered by ajfour last updated on 23/May/17

T = k x = m g

T_{1} = k (5 c m) = (0.5 k g) (9.8 m / s^{2})

T_{1} = k (\frac{1}{20} m) = 4.9 N a l s o \Rightarrow k = 98 N / m

T_{2} = k (x + Δ x) = (98 \frac{N}{m}) (0.07 m)

T_{2} = 6.86 N .

Commented by tawa tawa last updated on 23/May/17

God bless you sir .