Answer:
B=
≅8.06
Explanation:
Applying the Pythagorean theorem:
=
+ 
Here, C denotes the hypotenuse length, while A and B signify the lengths of the other two sides of the triangle. We can calculate B's length knowing the hypotenuse is 9 and A is 4.
=
+ 
81= 16+ 
81-16= 
B=
≅8.06
The string does not experience any force of tension, as it balances two forces acting in the same direction. Hence, the tension is zero.
Explanation:
If tension existed in the string, it would mean that two equal but opposite forces are exerting pull in contrary directions.
When a force of f newtons is applied from the right and another force of f newtons from the left, the resulting action occurs through one force. Because there is action on the same string in opposing directions, the tension in the string can only be equal to the magnitude of the string itself.
Therefore, the string indeed has no tension since it is dealing with two forces acting in the same direction. Thus, the tension is zero.
Answer:

Explanation:
Transformation of Energy
Also known as energy conversion, this refers to the process in which energy shifts from one type to another. In this context, three energy forms are involved. When the object is stationary at the ramp's peak, it possesses gravitational potential energy, calculated as

As the object descends the frictionless ramp, it converts all its potential energy into kinetic energy, represented as

Thus,

Ultimately, when the object encounters a rough surface, all energy converts to thermal energy. The work performed by the friction force corresponds to the alteration in kinetic energy, as all velocity is lost in this process:

Given the kinetic energy equals the initial potential energy:

The negative sign indicates that the work acted against the direction of movement, meaning the force and displacement are 180° apart.
This outcome is independent of the distance D needed to halt the block or the kinetic friction coefficient.