Question

Mass of a block of metal is 10 kg and its dimensions are length 50 cm, breadth 10 cm, height 20 cm. (See fig.) If the metal block is placed on the following suface on the table, find out on which of the surface ABCD, CDEF and BCFG will the pressure exerted on the table be maximum.

Answer 1

Given : Weight of the block = mg =10 x 9.8N =98 N
For the surface ABCD,
length = 50 cm,
height = 20 cm.
Area = 50 cm x 20 cm = 1000 cm2 = 0.1m2
Pressure = weight /area = 98/ (0.1) = 980 Pa
For the surface CDEF,
length = 50 cm
breadth = 10 cm
Area = 50 cm x 10 cm = 500 cm2 = 0.05 m2
Pressure = weight /area = 9800 /5 = 1960 Pa
For the surface BCFG,
height = 20 cm
breadth = 10 cm
Area = 20 cm x 10 cm = 200 cm2 = 0.02 m2
Pressure = weight/ area = 98 N/ 0.02 m2 = 4900 Pa : Maximum Pressure.
Hence, smaller the area of contact, larger is the pressure.