A uniform metre scale can be balanced at the 70.0 cm mark when a mass of 0.05 kg is hung from the 94.0 cm mark. Find the mass of the metre scale.
A uniform metre scale can be balanced at the 70.0 cm mark when a mass of 0.05 kg is hung from the 94.0 cm mark. Find the mass of the metre scale.
The correct option is D 60 g
The required diagram is shown below. In the diagram, AB is the uniform metre scale which is balanced horizontally at O.
Let M be the mass of the metre scale. Then as the metre scale is uniform, its weight will act at its midpoint, i.e., 50 cm mark. The mass M of the metre scale produces an anticlockwise moment about O and suspended weight produces clockwise moment.
Anticlockwise moment about O = M x 20
=20M
Clockwise moment about O = 50 x 24
= 1200
According to the principle of moments:
Anticlockwise moment = Clockwise moment
or 20M = 1200
or M = 1200/20 = 60 g
60 g
The required diagram is shown below. In the diagram, AB is the uniform metre scale which is balanced horizontally at O.
Let M be the mass of the metre scale. Then as the metre scale is uniform, its weight will act at its midpoint, i.e., 50 cm mark. The mass M of the metre scale produces an anticlockwise moment about O and suspended weight produces clockwise moment.
Anticlockwise moment about O = M x 20
=20M
Clockwise moment about O = 50 x 24
= 1200
According to the principle of moments:
Anticlockwise moment = Clockwise moment
or 20M = 1200
or M = 1200/20 = 60 g
