saumyajnverma
Answered

A girl weighing 45 kg is standing on pencil heels, each having an area of cross-section of ( 1 cm square ). An elephant weighing 2500kg and having a foot area of cross-section ( 240 cm square) is standing on the floor. which of the two exerts more pressure on the floor ? (g=10m/s (square) )

Answer :

TPS
weight of girl = 45 kgf 
area of cross section of one heel = 1 cm²
area of cross section of two heel = 1×2 = 2 cm²
Weight of girl = mg = 45×10 = 450 N
[tex]Pressure = \frac{weight}{area} = \frac{450\ N}{2\ cm^2} =225\ N/cm^2[/tex]

weight of elephant = 2500 kgf
area of cross section of one foot = 240 cm²
area of cross section of four feet = 240×4 = 960 cm²
Weight of elephant = mg =2500 ×10 = 25000 N
[tex]Pressure = \frac{weight}{area} = \frac{25000\ N}{960\ cm^2} =26\ N/cm^2[/tex]

So the girl with pencil heels exerts more pressure.
Jemma
The girl exerts more pressure because the area of application of force in case of the girl(2cm^2) is very low compared to the elephant. (880cm^2)

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