It is preferable to use air bags in the cars to protect the driver during accident , The colliding of a large truck with wall is more destructive than the colliding of a small...
When any object moves through the water (such as the fish, the swimmer, the dolphin, and the ship), there is a friction force arises between this object and the water which is called water...
When a solid object moves in the air, a friction force arises between the object and the air, This type of friction is called the air resistance and it acts in the opposite direction...
Friction arises when two solid objects touch each other, When the friction force is larger than the movement force, the body does not move, when the friction force is smaller than the movement force,...
