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