Define:
frictional force
Normal reaction force
tension force
Restoring force
1-Force that resists sliding or rolling of one solid object over another. Some friction is beneficial, such as the traction used to walk without slipping. Most friction, though, is undesirable opposition to motion, such as between moving parts of machines. For example, about 20% of the work done by an automobile engine is needed to overcome friction between moving parts. Friction is a result of attractive forces between the contact regions of two bodies, and the amount of friction is almost independent of the area of contact. Kinetic friction arises between surfaces in relative motion, static friction acts between surfaces at rest with respect to each other, and rolling friction occurs when an object rolls over a surface.
2-
Normal reaction force or normal force is the the force which acts perpendicular to the plane, on which an object is lying.
e.g. weight of an object resting on a table is balanced by normal force(N) exerted by the table.
N = mg.
Some examples of reaction force:-
Horse pulling a cart
The horse can pull and move a cart by exerting a force on the ground. In turn, the horse experiences a reaction force of equal magnitude in the opposite direction that causes the cart to move in that direction.
In this case, the action force is the force applied by the horse on the ground and reaction force is the force experienced by the horse from the ground.
Rockets
Rockets work on the principle of Newton’s III rd law of motion. In rockets, large amounts of hot gases are allowed to exit through a narrow opening. The fast moving gases exert a force on the rocket that in turn pushes the rocket upward.
In this case,
Action force → Exerted by the rocket on the exhaust gases
Reaction force → Exerted by the gases on the rocket
3-
- The tension force is the force which is transmitted through a string, rope, cable or wire when it is pulled tight by forces acting from opposite ends.
- The tension force is directed along the length of the wire and pulls equally on the objects on the opposite ends of the wire.
4-Restoring force is the force restores the shape of a deformed solid object to its original shape. It is an internal force that is developed due to the objects elastic nature. Example: When you leave the ball that you have been pressing in the previous example, the ball regains its original shape. This is due to its restoring force.
Regards