Question

A cube is on the ground. Each side is 50cm. The cube has a mass of 20kg. How much pressure does it exert on the ground?

Answer 1

Step-by-step explanation:

We know that

F = ma

Here,

a = g = 10 m/s²

So,

F = mg

=> F = 20 × 10

=> F = 200 N

now,

As 1 m = 100 cm

50 cm = 50/100 = 0.5 m

=> SA of cube = 6a²

=> SA = 6(0.5)²

=> SA = 6 × 0.25

=> SA = 1.5 m²

Now,

P = F/A

=> P = 200/1.5

=> P = 2000/15

=> P = 400/3

=> P = 133.3 Pa

Answer 2

We know that,

Pressure = Force ÷ Area

First let's find the force of the cube.

F = m × g

= 20 kg × 10 ms⁻²

= 200N

Now let us find the Area of the cube.

A = 6 a²

= 6 ×
`(50)/(100)` ×
`(50)/(100)`

= 1.5 m²

Now let us find the pressure.

Pressure = Force ÷ Area

= 200 N ÷ 1.5 m²

= 133 . 33 N m⁻² / 133 . 33 Pa

Hope this helps you :-)