Question

A ruler scale is balanced with two fingers, $F_1$ and $F_2$ at a separation 20 cm and 40 cm from the centre of the scale O respectively. If the person balancing the ruler tries to bring his fingers closer to the centre, which finger will slide first?

• A. $F_1$
• B. $F_2$
• C. Both simultaneously
• D. Insufficient data

Answer 1

Answer: (B)

$F_2$

As explained, the farther finger will exert lower force. This will reduce the frictional force on that finger and it slides. In this case the same happens with Finger 2.