Please post in English so i or someone else can help you.
Answer:
(A) = 3.57 m
Explanation:
from the question we are given the following:
diameter (d) = 3.2 m
mass (m) == 42 kg
angular speed (ω) = 4.27 rad/s
from the conservation of energy
mgh = 0.5 mv^{2} + 0.5Iω^{2} ...equation 1
where
Inertia (I) = 0.5mr^{2}
ω = \frac{v}{r}
equation 1 now becomes
mgh = 0.5 mv^{2} + 0.5(0.5mr^{2})(\frac{v}{r})^{2}
gh = 0.5 v^{2} + 0.5(0.5)(v)^{2}
4gh = 2v^{2} + v^{2}
h = 3v^{2} ÷ 4 g .... equation 2
from ω = \frac{v}{r}
v = ωr = 4.27 x (3.2 ÷ 2)
v = 6.8 m/s
now substituting the value of v into equation 2
h = 3v^{2} ÷ 4 g
h = 3 x (6.8)^{2} ÷ (4 x 9.8)
h = 3.57 m
Since his line of sight 63 degrees makes with the tip of the building
Tan63° = height of building / Horizontal distance
tan63° = Height / 50
50tan63° = Height
Height = 50tan63°
Height ≈ 50*1.9626
Height ≈ 98.13 m
Height of the building is ≈ 98.13 m. Mind you in solving for this height we have neglected the height of Daniel.
The height of building actually should be 98.13 m plus the height of Daniel. Since the 63° was measured from his eye level.
Answer:

Explanation:
Thrust is known as a reaction force which appears when a system expels or accelerates mass in one specific direction. If we know the acceleration and the mass of the air expelled by the jet engine, we can compute the thrust
.
The acceleration is calculated by using the dynamics formula

The values are


The thrust is

Answer:
1. The force of the shelf holding the book up.
Explanation:
The free body diagram of the book is as follows:
1 - The weight of the book towards downwards
2 - The normal force that the shelf exerts on the book towards upwards.
Since the book is at rest, these two forces are equal to each other and according to Newton's Third Law the reaction force to the force of gravity is equal but opposite to the weight of the book. This reaction force is the one that holds the book up on the shelf.