question_answer

A meter scale is balanced at its mid-point if a 20N weight is balanced at 20 cm mark and a 30 N weight is hanged at x cm mark. Calculate the value of x.

A) 20 cm              

B)        70 cm

C) 30 cm              

D)        80 cm

Correct Answer: B

Solution :

[b] \[{{m}_{1}}g=20N;{{m}_{2}}g=30N\Rightarrow {{m}_{1}}g{{\ell }_{1}}={{m}_{2}}g{{\ell }_{2}}\] \[\therefore 20\times 30=30{{\ell }_{2}};\,\,\therefore {{\ell }_{2}}=20cm;\] \[\therefore x=\left( 50+20 \right)\] \[=70\text{ }cm\]