Thrust
In our fifth blog of the series, we discussed forces. As a force is any interaction when unopposed, will change the state of the object. From the same blog we are also familiar with the concept of net force.
When a net force is applied in a particular direction in a small fraction of time is termed as thrust.
Thrust is a kind of an instantaneous push, pull or interaction. When a system pushes or accelerates mass in one direction, there is a thrust in the opposite direction. In physics, this concept is described in Newton’s second and third laws. Thrust can be used for many kinds of vehicles and engines such as rockets, motorboats, and jet engines etc. Thrust is measured in newtons in the metric system.
The concept of thrust is very popular in the daily life of human beings. Some obvious examples are, inserting a drawing pin in a notice board to fix the poster and hammering the nail to fix it in the wall.
Pressure
Whenever the force is applied on any surface, it gets distributed all over the surface. The force per unit area is termed as pressure. Physics define it as,
Pressure is the force applied perpendicular to the surface of an object per unit area over which that force is distributed.
Various units are used to express pressure. Some of these are derived from a unit of force divided by a unit of area, for example, Newton per meter square (N/m2). The SI unit of pressure, the pascal (Pa).
From our daily life observation, we know that all the pins, nails, sticks, or rod having a narrow pointing end get inserted easily. Whereas, if any of the rod end is not narrow, it would be difficult to insert it in the wall.
That narrow end always has a very small surface area with respect to the surface area of the other object. If the surface area of the narrow end is increased, it would not be easy for the nail to penetrate the wall. Because the applied net force on the nail will be distributed all over the surface of the pointing end and net force will be decreased. In physics, this kind of divided force is termed as pressure.
It is very interesting to know that pressure is inversely proportional to the surface area of the pointing end. Hence, as surface area decreases, pressure increases and as surface area is increased, pressure decreases. That’s why nails, pins, knives etc. have sharp and pointing ends and buildings, wheels etc. have wide surface area in contact with ground. This makes them useful for humans.
So, that’s enough for now, see you in the next blog, until then keep exploring and enjoying the beauty of physics.
