Force Scalar or Vector? | Physics | Don't Memorise

Transcript

look at this rectangular object kept on the table are there any forces acting on it yes there is a gravitational force acting pulling it down and an equal and opposite normal force pushing it up. as the forces are balanced the net force is zero. and hence the object will continue to be addressed unless another external force acts on it now if we push the object towards the right what happens the object moves towards the right,correct yes that's because the applied force towards the right and the forces were unbalanced did you notice how we draw the action of forces yes we use arrows yes and that should tell us an important thing about force it is a vector quantity it has magnitude and direction we can say that we apply a force of 5N towards the right dont worry about the units of force we will understand it later but for now understand that force is a vector quantity if we would have said that we applied a force of 5N to the subject you wouldn't know how the force is applied and in which direction the object would move it could have been in any direction but the fact that we said right it means that it will be in this direction which are the forces that acted on the object when it moved to the right there was this force which we applied then were forces of air resistance and friction towards the left. then why did the object still move towards the right ? the upward and downward forces cancel each other so the question of the object moving upwards and downwards will not arise. so i move towards the right because the force of 5N is more than the sum of these two forces acting towards the left, also notice the size of the arrows if the magnitude is more the size is also larger.

this diagram you see here is called the free body diagram. Looking at it will give us a overall idea if the forces are balanced or not. and that in turn will also give us an idea about the direction in which the object is going to move the best way to understand force is by understanding free body diagrams in the next lesson we will look at a few interesting examples based on this concept.