A force is a vector quantity because it has both Magnitude and direction Mass and velocity Action and reaction counterparts Speed and direction A tree stump is pulled northward by a 10-N force at the same time a 25-N force pulls it southward. The resultant force has a magnitude of ON 15N 25 N 150 N The first scientist to introduce the concept of inertia was Aristotle Galileo Newton Copernicus

1. A force is a vector quantity because it has both magnitude and direction. This means that a force has both a size (magnitude) and a direction in which it acts. This is why forces are often represented as arrows, with the length of the arrow representing the magnitude of the force and the direction of the arrow representing the direction of the force.<br /><br />2. The resultant force on the tree stump is the difference between the two forces because they are acting in opposite directions. The 10-N force is pulling the stump northward, while the 25-N force is pulling it southward. To find the resultant force, we subtract the smaller force from the larger force: 25 N - 10 N = 15 N. Therefore, the resultant force has a magnitude of 15 N.<br /><br />3. The first scientist to introduce the concept of inertia was Galileo. Inertia is the tendency of an object to resist changes in its state of motion. Galileo's work on inertia laid the foundation for Newton's laws of motion, which further developed the concept of inertia.