Science Made Easy
Mass:
• Mass of an object is the measure of its inertia.
• It is the matter present in it. It remains the same everywhere in the universe.
Weight:
• The force of attraction of the earth on the object is known as the weight of the object.
• It’s S.I. unit is Newton.
W = m x g
Thrust:
• The force that acts in the perpendicular direction is called thrust.
• It is similar to force applied to an object
• It is a vector quantity.
Pressure
• The force that acts per unit area of the object is pressure.
• It is the thrust per unit area.
• Pressure is denoted by ‘P'
• P = thrust/ area = force/ area = F/A
• SI unit: N/m2 or Pa (Pascal)
Applications of pressure
• The base of high buildings is made wider so that weight of the walls act over a large surface area and pressure is less.
• School bags are having broad strap so that the weight of the school bags fall over a large area of shoulder and produce less pressure and become less painful.
• All liquids and gases exist pressure in all direction.
