A constant net force acts on an object moving in a straight line - NSC Physical Sciences - Question 1 - 2021 - Paper 1

In this scenario, since a constant net force is acting on the object, it implies that the mass of the object is unchanged and the acceleration is constant due to Newton's second law of motion:

$F = ma$

Where:

• F = net force
• m = mass
• a = acceleration

Given that the force is constant, the acceleration must also be constant. However, momentum, which is defined as the product of mass and velocity (i.e., $p = mv$), will not remain constant as the velocity of the object will change due to the acceleration imparted by the net force. Therefore, the correct constant quantity is:

C. Acceleration.