Answer:
2.17 Mpa
Explanation:
The location of neutral axis from the top will be

Moment of inertia from neutral axis will be given by 
Therefore, moment of inertia will be
![\frac {240\times 25^{3}}{12}+(240\times 25)\times (56.25-25/2)^{2}+2\times [\frac {20\times 150^{3}}{12}+(20\times 150)\times ((25+150/2)-56.25)^{2}]=34.5313\times 10^{6} mm^{4}}](https://tex.z-dn.net/?f=%5Cfrac%20%7B240%5Ctimes%2025%5E%7B3%7D%7D%7B12%7D%2B%28240%5Ctimes%2025%29%5Ctimes%20%2856.25-25%2F2%29%5E%7B2%7D%2B2%5Ctimes%20%5B%5Cfrac%20%7B20%5Ctimes%20150%5E%7B3%7D%7D%7B12%7D%2B%2820%5Ctimes%20150%29%5Ctimes%20%28%2825%2B150%2F2%29-56.25%29%5E%7B2%7D%5D%3D34.5313%5Ctimes%2010%5E%7B6%7D%20mm%5E%7B4%7D%7D)
Bending stress at top= 
Bending stress at bottom=
Mpa
Comparing the two stresses, the maximum stress occurs at the bottom and is 2.17 Mpa
Answer:
The change in gravitational potential energy is -1.80x10⁵ J.
Explanation:
The change in gravitational potential energy is given by:


Where:
"i" is for final and "f" for final
m: is the mass
g: is the gravity = 9.81 m/s²
h: is the height
For the car and the passengers we have:
The minus sign is because when the elevator car and the passengers are up they have a bigger gravitational potential energy than when they are in the ground.
Therefore, the change in gravitational potential energy is -1.80x10⁵ J.
I hope it helps you!
Answer: 5,640 s (94 minutes)
Explanation:
the tangential speed of the HST is given by
(1)
where
is the length of the orbit
r is the radius of the orbit
T is the orbital period
In our problem, we know the tangential speed:
. The radius of the orbit is the sum of the Earth's radius and the distance of the HST above Earth's surface:

So, we can re-arrange equation (1) to find the orbital period:

Dividing by 60, we get that this time corresponds to 94 minutes.
Answer:
Emechanical=mgh+
mν²
Explanation:
The equation for the total mechanical energy is:
Emechanical=Epotential+Ekinetic
In which,
Epotential=mgh; m: mass of the body, g: gravity; h: height
Ekinetic=
mν²; m: mass of the body, ν: velocity of the body
So,
Emechanical=mgh+
mν²
1. The chemical reaction produced by Carlo's fire is exergonic because energy is "going out". As the reaction proceeds, entropy increases as the energy stored in the dry wood and leaves are used up as fuel to create the fire which produces low quality light and warmth.
2. This reaction is a classic example of an exothermic reaction. Exothermic reactions are characterized with the presence of heat and light in the products. Combustion reactions are always exothermic in nature.
3. Catalyst are substances that are used to speed up reactions by lowering the activation requirement. Catalysts aren't consumed in the reaction and can still be chemically retrieved afterwards. In this situation, the leaves cannot be retrieved after the reaction ends. The leaves speed up the heating of the wood but it does not behave as a catalyst.