Question

Two bodies. A and B. collide as shown in figures a and b below. Circle the true statement:

• A. They exert equal and opposite forces on each other in (a) but not in (b)
• B. They exert equal and opposite force on each other in (b) but not in (a)
• C. They exert equal and opposite force on each other in both (a) and (b)
• D. The forces are equal and opposite to each other in (a), but only the components of the parallel to the velocities are equal in (b).

Answer 1

Answer: (C)

They exert equal and opposite force on each other in both (a) and (b)

Answer 2

Newton's Third Law of Motion states that for every action, there is an equal and opposite reaction. This fundamental law applies universally to all interactions, including collisions between objects, regardless of the geometry of the collision (head-on or oblique).

• In Figure (a) (Head-on Collision): The bodies A and B collide directly along the line connecting their centers. During this interaction, body A exerts a force on body B, and simultaneously, body B exerts an equal and opposite force on body A. This is a direct application of Newton's Third Law.

• In Figure (b) (Oblique Collision): The bodies A and B collide such that their initial velocities are not along the line connecting their centers. Even in this scenario, the forces of interaction between the two bodies still obey Newton's Third Law. The force exerted by A on B will be equal in magnitude and opposite in direction to the force exerted by B on A. The forces act along the line of impact (the line connecting the centers of the spheres at the moment of impact). The fact that it's an oblique collision affects how momentum and kinetic energy are conserved along different axes, but it does not change the nature of the interaction forces themselves.

Therefore, in both types of collisions (head-on and oblique), the forces exerted by the bodies on each other are always equal in magnitude and opposite in direction.