In this post, we will solve selected Pressure problems or numerical with the pressure formula or equation. Before that let’s quickly find the definition, formula, and SI unit of pressure.
The pressure is the force per unit area that is applied on the surface of an object. Pressure increases if the force applied increases, and decreases if the area of contact increases.
Pressure Formula or equation
Pressure can be calculated from this formula or Pressure equation
Pressure = Force /Area
P = F/A
Pressure Unit in SI
The unit of pressure in the SI system is the pascal, abbreviated Pa. One pascal is equal to a force of 1 N applied over an area of 1 m^2, or 1 Pa = 1 N/m^2.
Pressure problems – solving numerical with pressure formula
1 ] A water glass sitting on a table weighs 4 N. The bottom of the water glass has a surface area of 0.003 m^2. Calculate the pressure the water glass exerts on the table.
2] A student weighs 600 N. The student’s shoes are in contact with the floor over a surface area of 0.012 m^2. Calculate the pressure exerted by the student on the floor.
3] A box that weighs 250 N is at rest on the floor. If the pressure exerted by the box on the floor is 25,000 Pa, over what area is the box in contact with the floor?
4] If You are holding a 2-kg book in the palm of your hand and if the area of contact between your hand and the book is 0.003 m^2 then find out the pressure that is exerted on your hand by the book
Force or thrust here =F= 4 N
Area A = 0.003 m^2
Pressure exerted = P = F/A = 4/0.003 Pa = 1333.33 Pa
Force or thrust here =F=600 N
Area A = 0.012 m^2
Pressure exerted = P = F/A = 600/0.012 Pa = 5 x 10^4 Pa
Force or thrust here =F=250 N
Pressure exerted = P = 25,000 Pa
So the Area in contact A =F/P= 250/25000 m^2 = 0.01 m^2
Force = F = 2 x 9.8 N = 19.6 N
Area = 0.003 m^2
Pressure = F/A = 19.6/0.003 Pa =6533.33 Pa