Question

When a force of $1$ newton acts on a mass of $1kg$ that is able to move freely, the object moves with a/an :
A. Speed of $1m{s^{ - 1}}$
B. Acceleration of $1m{s^{ - 2}}$
C. Speed of $1km{s^{ - 1}}$
D. None of these

Answer 1

We know that Newton’s laws of motion describe the relationship between a body and the forces acting upon it. So we can solve this problem with help of Newton's laws of motion. There are three laws of motion. The first law of motion explains the law of inertia. The first law states that the body remains at rest or in moving with uniform velocity unless a force acts upon it.. Hence the net force on the body is zero, the velocity remains constant. This is known as uniform motion.

Complete step-by-step solution:
Newton’s second law states that the rate of change of the momentum is equal in both magnitude and direction to the force acting on it. A force can change the momentum of the body. The equation for the second law is the following:
$F = \dfrac{{dp}}{{dt}} = \dfrac{{d\left( {mv} \right)}}{{dt}} = m\dfrac{{dv}}{{dt}} = ma$
Where $F$ is the net force applied, $p$ is the momentum of the body, $v$ is the velocity of the body, $m$ is the mass of the body and $a$ is the acceleration of the body. So the net force applied to a body produces a proportional acceleration.
In the given question, $F = 1N$ and $m = 1kg$ then,
$a = \dfrac{F}{m} = \dfrac{{1N}}{{1kg}} = 1m/{s^2}$
Option B is correct. When a force of $1$ newton acts on a mass of $1kg$ that is able to move freely, the object moves with an acceleration of $1m{s^{ - 2}}$.
Newton’s third states that when two bodies interact, they apply forces to one another which are equal in magnitude and opposite in direction. This law is also known as the law of action and reaction.

Note: We know that Newton's laws of motion are helpful for defining the force and its effects on the object when the force is applied. Hence force can change the state of an object and its direction of motion.