Raj placed an iron cuboid of dimensions 4cm× 7cm× 10 cm on a tray containing sand. If mass of cuboid is 2.24 kg, find the minimum pressure on sand as calculated by him?
Answers
Answer:
∴ Mass of cuboid = Volume x Density
= (4 cm x 7 cm x 10 cm) x 8 gcm-3
[∵ Volume of cuboid = l x b x h]
= 2240 g = 2.24 kg
Force applied by the cuboid on the sand
= mg = 2.24 x 10 = 22.4 N [∵ g = 10 ms-2)
Pressure will be minimum when area of the face of cuboid kept on sand is maximum, i.e. in the case of face with 7 cm x10 cm.
Area of the face = 7 cm x 10 cm = 7/100m x 10/100m
= 0.07 m x 0.1 m = 0.007 m2
Minimum pressure = force/area = 22.4/0.007
= 3200 Nm-2
Pressure will be maximum when area of face of cuboid kept on the sand is minimum, i.e. in the case of face with 4 cm x 7cm.
Area of the face = 4 cm x 7 cm
= 4/100m x 7/100
m = 0.0028m2
Maximum pressure = force/area= 22.4/0.0028
= 8000 Nm-2