A uniform pencil ab weighting 40g can be balanced horizontally on a knife edge at 2cm from the end a when a mass 60g is hung from this end what is the length of a pencil ?

Let the length of the pencil be x cm.

The torque due to the pencil is equal to the torque due to the mass hanging from the end.

Torque due to the pencil = Torque due to the mass

40g * 2cm = 60g * (x - 2)cm

80 = 60x - 120

60x = 200

x = 200/60

x = 3.33 cm

Therefore, the length of the pencil is 3.33 cm.