Question

please solve this question

Answer 1

We have,
Diameter of the graphite cylinder = 1 mm=1÷10 cm.
therefore, Radius of the graphite cylinder= 1÷20 cm
Length of the graphite cylinder = 10cm
Volume of the graphite cylinder = 22÷7×1÷20×1÷20×10 cm cube= 0.0785714285.
The diameter of pencil = 7mm = 7÷10cm
Therefore, Radius of pencil = 7÷20cm and, length of pencil =10cm
Therefore, volume of pencil = 22÷7×7÷20×7÷20×10cm cube
=3.85cm cube
(volume of wood) - ( volume of pencil)
3.85-0.0785=3.37715 cm cube.
Now we have ,
Specific gravity of wood = 0.7 gm/cm cube.
and, specific gravity of wood graphite =2.1 gm/cm cube
Therefore, weight of the pencil = Volume of wood × specific gravity of wood + volume of graphite × specific gravity of
=(3.37715×0.7+0.0785×2.1)gm
=2.528855 gm