Question

A block of glass measures 2 cm by 3cm by 5 cm. Given that the density of glass is 2.5 g/cm3, determine: lowest and maximum pressure it can exert on a flat surface.

Answer 1

Therefore, pressure is inversely proportional to area, i.e. bigger area equals less pressure, smaller area equals bigger pressure.

So, we would want to apply the force on the face of the block with the smallest dimensions if we want to find the largest pressure, i.e. that is

0.1

m

by

0.05

m

, and

A

=

0.1

m

⋅

0.05

m

=

0.005

m

2

.

So, the maximum pressure will be

P

=

37.5

N

0.005

m

2

=

7500

Pa

.

If we want to apply the least possible pressure, we must apply the force on the face with the biggest dimensions, and that is

0.3

m

by

0.1

m

, and

A

=

0.3

m

⋅

0.1

m

=

0.03

m

2

.

Therefore, the pressure here will be

P

=

37.5

N

0.03

m

2

=

1250

Pa