Question

Which statement is true according to Newton's second law of motion?

Answer 1

According to Newton's second law we have:

F = ma

Where,

F: Sum of forces or net force applied

m: total mass of the object

a: acceleration of the object

We observe that the force and the acceleration are proportional, being the constant of proportionality the mass of the object.

Therefore, the object accelerates in the same direction as the applied force.

Answer:

An object accelerates in the same direction as that of the force applied.

Answer 2

The correct answer to the question is C).An object accelerates in the same direction as that of the force applied.

EXPLANATION:

Before going to answer this question,  first we have to understand Newton's second laws of motion.

As per Newton's second laws of motion, the rate of change of momentum is directly proportional to the net external force and takes place along the direction of force.

Mathematically $F =\ \frac{dP}{dt}$

Here, P is the momentum and P = mv.

                         ⇒ F = $\frac{d}{dt}(mv)$

                                 = $m\frac{d}{dt}(v)$        [m = constant]

                                 = ma.

Here, m  and v are the mass and velocity of a body .

'a' stands for the acceleration of a body which is the rate of change of velocity.

In vector form it can be written as $\vec F=\ m\times\vec a$.

Hence, it is obvious that the net external force is the product of mass with acceleration.

As mass is a scalar quantity, so we can say that force is simply the scalar multiple of mass with acceleration.

Hence, the direction of acceleration will be along the direction of force.