Question

It is easier to cut with a sharp knife than a blunt one, This is because
A. Sharp knife exerts more pressure
B. Sharp knife exerts less pressure
C. Both knives exert equal pressure
D. Sharp knife has a better grip

Answer 1

Hint: The question is based on pressure. Pressure is the perpendicular force acting on a unit surface area of an object over which the applied force is distributed. Pressure is a scalar quantity. Now using this to find why It is easier to cut with a sharp knife.

Complete step by step answer:
Now from the question,
Pressure is the force applied at right angles to the surface of an object per unit area. Mathematically it is written as:
Pressure p= F/A
Where ‘p’ is the pressure; ‘F’ is the magnitude of the normal (applied perpendicularly) force; ‘A’ is the area of the surface in contact.
Now, The pressure exerted by the edge of the sharp knife is much more than that exerted by the blunt one because the surface area on which force is applied with a sharp knife is very small and as from the definition of pressure the less the surface area on which the force is applied the greater is the pressure. Therefore, it is easier to cut with the sharp knife than with that of a blunt knife.

So, the correct answer is “Option A”.

Note:
Pressure is described in various units. The SI unit of pressure is pascal (Pa) similarly, the pound-force per square inch (psi) is the traditional unit of pressure in the imperial and U.S. customary systems. Pressure can also be expressed in the terms of standard atmospheric pressure; the atmosphere (atm) is equal to this pressure, and the torr is defined as 1⁄760 of this. Different manometric units such as the centimetre of water, millimetre of mercury, inch of mercury are used to express pressures in the terms of height of column of that particular fluid in a manometer.