The frictional force is 218.6 N
Explanation:
The block in the problem is at rest along the inclined surface: this means that the net force acting along the direction parallel to the incline must be zero.
There are two forces acting along this direction:
- The component of the weight parallel to the incline, downward along the plane, of magnitude

where
m = 46 kg is the mass
is the acceleration of gravity
is the angle of the incline
- The (static) frictional force, acting upward, of magnitude 
Since the block is in equilibrium, we can write

And substituting, we find the force of friction:

Learn more about frictional force along an inclined plane:
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Explanation:
The dimension of the book is 1.75 m × 2.25 m. If the book ends up at its initial position. The displacement of the book is equal to zero as the object reaches to its initial position.
If it completes its motion in 23 s, t = 23 s
Total displacement of the book is equal to its perimeter. It is given by :

The net displacement divided by total time taken is called the average velocity of an object. Here, the displacement is 0. So, average velocity is 0.
The average speed of an object is given by :


v = 0.347 m/s
So, the average speed of the book is 0.347 m/s. Hence, this is the required solution.
Then everyone would fall off the surface
This question sounds like it came after some activity where
some forces were observed. Since we were not there, and
we don't know what the activity was, we don't know what forces
were observed, and we have no clue to how they might be related
to the motion of the Earth around the sun.