Correct Answer - Option 3 : m
CONCEPT:
-
Newton’s Second Law of Motion: The rate of change of linear momentum of a body is directly proportional to the external force applied on the body and this change takes place always in the direction of the applied force.
- According to the second law of motion, force
\(Force \propto \frac{{change\;in\;momentum}}{{time}}\)
\(⇒ F = K\frac{{{p_2} - {p_1}}}{t} = K\frac{{m\left( {v - u} \right)}}{t} = Kma\) \(\left[ {\therefore \frac{{v - u}}{t} = a} \right]\)
Where, K = constant of proportionality, p = momentum of the body, m = mass of the body, u = initial velocity of the body, v = final velocity of the body, and a = acceleration of the body.
EXPLANATION:
Given that:
momentum (p) = mt + n
According to the second law of motion, force
\(⇒ F =\frac{dp}{dt}\)
\(⇒ F = \frac{d(mt +n)}{dt}\)
⇒ F = m + 0 = m = constant
- Since the force is always constant which is equal to m. So at time t = 1 second, the force will be equal to m.
- Therefore option 3 is correct.
