Question

Compared to the force needed to start sliding a crate across a rough level floor, the force needed to keep sliding once it is moving is

1) less

2) greater

3) the same

Answer 1

The force required to keep a crate sliding once it's in motion is less (Option 1) than the force needed to start sliding it because static friction is greater than kinetic friction.

Step-by-step explanation:

Compared to the force needed to start sliding a crate across a rough level floor, the force needed to keep it sliding once it is moving is less (Option 1). The difference in force required is due to static friction being larger than kinetic friction. When you first try to move a crate, static friction must be overcome, which requires a greater force. Once the crate starts sliding, only kinetic friction opposes the motion, which is smaller, and hence less force is needed to maintain the movement.

Answer 2

Greater

Step-by-step explanation:

As we know that when an object is placed on a rough floor then minimum force required to slide the object on the rough surface is known as limiting friction force.

Limiting friction is the maximum value of static friction between the object and ground surface.

So it is given as

`f_s = \mu_sF_n`

Once the object start sliding on the rough surface then the friction force on the object is known as kinetic friction which is given by

`f_k = \mu_kF_n`

now we know that

`\mu_s \geq \mu_k`

So it requires less force to move an object on rough floor once it starts sliding

So the force required to start sliding is greater than the force to move it once it start sliding