Question

what does 9.8 N/kg mean?

Answer 1

Hint: Newton is the S.I. unit of force, and the kg is the S.I. unit of the mass. When we divide the force with the mass then we get the force acting on per unit mass.



Formula used:
\[F = ma\], here F is the force acting on a body of mass m and a is the acceleration produced in the body due to application of the force.



Complete answer:
Newton's first law of motion which is also called the law of inertia determines the property of matter to resist change in state of motion. A body continues to be in state of rest or uniform motion unless any non-zero force is applied on it. The resistance to change in the state of the body is quantified in terms of mass. The S.I unit of mass is kg.

Newton's second law of motion states that the acceleration of the body is proportional to the magnitude of the force acting on the body.

Force is the physical quantity which changes or tends to change the state of motion, shape or size of the body on which it is applied.

The S.I unit of the force is Newton.
F=ma
If we write units then, ${N=kg m/{s^2}}$
Now ${N/kg = m/{s^2}}$
So, ${9.8N/kg = 9.8m/{s^2}}$
Implies,
9.8N/kg signifies that a gravitational field of 9.8N strength is needed to attract 1 kg mass toward the center of the earth.

Note: The gravitational field strength due to earth is inversely proportional to the distance from the center of earth. So it is constant till the height which is insignificant to the radius of the earth and it is equal to \[9.8N/kg\]