Is there any case when the direction of the resultant force (net force) is NOT along the direction of motion?

Answer 1

The resultant force and direction of motion are not related.

There are many cases where this may be shown. The easiest one to consider is circular motion. Here the resultant force is towards the centre of the circle and the immediate motionis tangentical to the circle.

Newton's Second Law tells us that any resultant force and the resulting acceleration are in the same direction.

Answer 2

When the net force is zero on an object, the body is either in uniform motion or at rest.
- Newton’s first law of motion.

Now if a number of forces act on the body, we can replace all of them by a single resultant force.

The resultant force now will act in any one particular direction depending upon the directions of forces (vector addition) added.

The direction of this resultant force can be at any angle to the direction of the uniform motion (velocity) which the object had prior to the resultant force acted.

The resultant acceleration will be in the direction of the resultant force.


If the initial direction of the velocity of the body coincided with the resultant acceleration of the force, the motion is rectilinear (in a straight line); the velocity may either decrease or increase according to the direction of acceleration.

In all other cases the motion is curvilinear and in particular if the direction of acceleration is perpendicular to the velocity it is circular in motion.

In projectile motion, the force acts always vertically down ward,but the direction of motion continuously changes.

Answer 3

yes of course there are many cases. The direction of motion gives direction of velocity. direction of force gives direction of acceleration. There is no compulsion for acceleration to be in same direction as velocity.
Example> uniform circular motion, where force is directed towards the center, and the body moves in a circle

Answer 4

Many people have cited the circular motion example, which is a clear and simple one. But here's one even simpler. Imagine a car driving west, and the driver hits the breaks. The force is certainly not west, but for some time, the motion is still west. Force and acceleration are related by Newton's second law, and it seems you mave have acceleration and motion confused.

Answer 5

yes
It is applied to the circular motion

Imagine that you are holding a string and at the end is a stone
Let the stone rotate in a circular motion
the only force exerted here is the centripetal force on the string that you are holding

direction of motion is tangent to the circle of motion
the force is perpendicular to it
OK

Answer 6

You mean when gravitational force makes a satellite curve in orbit by pulling perpendicular to the motion??

Answer 7

When the object is large enough that the initial force is not directed to the center of the object.
An example is a pool-table shot.

Answer 8

No,because it then cotradicts Newtons` second law of motion.