When a crate is moving on a track where friction is not negligible. The friction force is said to be
kinetic friction
static friction
Non existant
kinetic friction
non existant
The friction force that acts on a moving crate on a track is known as kinetic friction.
When a crate is moving on a track where friction is not negligible, the friction force is referred to as kinetic friction.
To understand why, let's start by explaining what kinetic friction is. Kinetic friction is the force that opposes the motion of an object when it is already in motion. This force arises due to the contact between the surfaces of the object and its surroundings. In the case of a crate moving on a track, the kinetic friction force arises from the interaction between the crate and the track's surface.
To determine whether the friction force in this situation is kinetic friction, static friction, or nonexistent, we need to consider the crate's motion. If the crate is already moving on the track, then it experiences kinetic friction. This friction force acts in the opposite direction to the crate's motion, slowing it down.
On the other hand, if the crate is stationary and not moving, then it experiences static friction. Static friction is the force that prevents an object from moving when an external force is trying to set it in motion. In this case, the static friction force acts in the direction opposite to the external force being applied to the crate.
If the crate is experiencing neither kinetic nor static friction, it means that there is no friction force acting on it. However, it's important to note that in most real-world scenarios, friction is never truly nonexistent. There will always be some friction present, even if it is very small.
So, in summary, when a crate is moving on a track where friction is not negligible, the friction force is referred to as kinetic friction.