Question

A man of mass $60\,\,Kg$ is standing on a weighing machine placed on ground. Calculate the reading of the machine. $\left( {g = 10\,\,m{s^{ - 2}}} \right)$

(A) $60\,\,N$
(B) $600\,\,N$
(C) $540\,\,N$
(D) $360\,\,N$

Answer 1

Hint: The given problem can be solved using one of the three laws that was proposed by Sir Isaac Newton, that is the formula derived from Newton's second law of motion which incorporates the mass of the man and the acceleration due the gravity.
The formula for finding the reading on the machine is given by the Newton’s second law of motion;
$W = mg$
Where, $W$ denotes the weight of the man standing on the weighing machine, $m$ denotes the mass of the man, $g$ denotes the acceleration due to gravity of the man on the weighing machine.

Complete step by step solution:
The data given in the problem are;
Mass of the man is, $m = 60\,\,Kg$,
Acceleration due to gravitational force, $g = 10\,\,m{s^{ - 2}}$.
The formula for reading on the machine is given as;
$W = mg$
That is,
Since the acceleration of the object is equal to the acceleration due to gravity.
$W = mg$,
Where, $g$ represents the acceleration due to gravity.
Substitute the values for the mass of the man standing on the weighing Machine and the acceleration due to the gravitational pull of earth that is acting on the man.
$\Rightarrow W = 60\,Kg \times 10\,m{s^{ - 2}}$
On simplifying the above equation, we get,
$\Rightarrow W = 600\,N$
Therefore, the reading on the machine when the man is standing on the weighing machine is $\Rightarrow F = 600\,\,N$.

Hence the option (B), $F = 600\,\,N$ is the correct answer.

Note: The value for the acceleration due to gravity is $g = 9.8\,\,m{s^{ - 2}}$, but we can round it off to the value of $g = 10\,\,m{s^{ - 2}}$, to keep the calculation difficulties to a minimum. In the above problem we use acceleration due to gravity, instead of acceleration because both of them are the same in case of gravitational force.