Answer:
Distance= 2.3864m
Explanation:
So that the balance is in equilibrium parallel to the floor, we must match the moment each man makes with respect to the pivot point.
In many cases the point of application of force does not coincide with the point of application in the body. In this case the force acts on the object and its structure at a certain distance, by means of an element that transfers that action of this force to the object.
This combination of force applied by the distance to the point of the structure where it is applied is called the moment of force F with respect to the point. The moment will attempt a rotation shift or rotation of the object. The distance from the force to the point of application is called the arm.
Mathematically it is calculated by expression:
M= F×d
The moment caused by the first man is:
M1= 75kg × (9.81m/s²) × 1.75m= 1287.5625 N×m
The moment caused by the second man must be equal to that caused by the first by which:
M2= 1287.5625 N×m= 55kg × (9.81m/s²) × distance ⇒
⇒distance= (1287.5625 N×m)/( (55kg × (9.81m/s²) )= 2.3864m
At this distance from the pivot point, the second should sit down so that the balance is balanced parallel to the ground.
Answer:

Explanation:
the variations in riser height or tread depth should not be grater than
that is equal to 9.5 mm but the maximum riser height should be the
but variation in riser height should not exceed to
. The minimum riser height should be 7 inches which is equal to the 178 mm
Answer: C- ecosystem
An ecosystem is a biological community in which living beings interacts with their non-living environment. An ecosystem consists of abiotic ( non-living factors like water, sunlight, wind and soil) and biotic factors such as plants and animals. Ecosystem allows not only the interaction of abiotic and biotic factors but it favors the interaction between the living species. For example animals are dependent upon plants so as to derive their food. The coexistence of organisms favors the diversity of land forms on earth.
Communities of organisms coexist in organized, balanced ecosystems.
The concept required to solve this problem is the optical relationship that exists between the apparent depth and actual or actual depth. This is mathematically expressed under the equations.

Where,
Depth of glass
Refraction index of water
Refraction index of glass
Refraction index of air
Depth of water
I enclose a diagram for a better understanding of the problem, in this way we can determine that the apparent depth in the water of the logo would be subject to



Therefore the distance below the upper surface of the water that appears to be the logo is 4.041cm
Gravity is the energy due to Earth pulling down on an object.