Question

A girl weighing 45 kg is standing on pencil heels, each having
an area of cross-section of 1 cm2. An elephant weighing 1500
kg and foot area of crosssection of 250 cm?, standing on the
floor. Which of the two exerts more pressure on the floor and by
how much? (Take g= 10 m/s2, F= mxg where F=
Force, m= mass, g= acceleration due to gravity.)​

Answer 1

Answer:

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

Pressure = \frac{weight}{area} = \frac{450\ N}{2\ cm^2} =225\ N/cm^2Pressure=

area

weight

=

2 cm

2

450 N

=225 N/cm

2

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

Pressure = \frac{weight}{area} = \frac{25000\ N}{960\ cm^2} =26\ N/cm^2Pressure=

area

weight

=

960 cm

2

25000 N

=26 N/cm

2

So the girl with pencil heels exerts more pressure.

Answer 2

see your answer in the attachment above