question_answer

In order to balance a see-saw of total length 10.0 m, two kids weighing 20 kg and 40 kg are 'sitting at an end and at a distance x from the fulcrum at the centre, respectively. The value x (in cm) is

A) 125

B) 250    

C) 450    

D) 350

Correct Answer: B

Solution :

Consider the figure given below. In balanced condition, net torque at the point O (fulcrum) is zero. \[\Rightarrow \]\[20\times 5=40\times x\]\[\Rightarrow \]\[x=\frac{20\times 5}{40}=25\]\[=250cm\]