Well Hmm how much you tell me it’s your work lol
To illustrate clearly, I will rewrite the reaction in a more understandable manner.
<span>2 Al(s) + Fe</span>₂O₃ (s) ⇒ 2 Fe(s) + Al₂O₃(s) Δ<span>hrxn = –850 kJ
This reaction has a negative sign for the change in enthalpy of reaction. The sign convention only means that the reaction releases energy to the surroundings. In other words, the reaction is exothermic. Focusing on only its magnitude, this means that 850 kJ of energy is needed for this reaction of 2 Aluminum moles and 1 mole of </span>Fe₂O₃ to occur.
Now, if you only had an energy of 725 kJ, then the reaction is incomplete but it will still form Iron (Fe). We use stoichiometric calculations as follows:
725 kJ * (2 mol Fe/850 kJ) = 1.7 moles of Fe
Knowing that the molar mass of Fe is 55.6 g/mol, then the mass of produced iron is
1.7 mol Fe * 55.6 g/mol = 94.85 g iron
This is a projectile motionm with
Iniital height, Yo = 2.4 m
Iniital vertical velocity, Voy = 0
Kind of motion: vertical fall => Y = Yo - Voy * t - [g*t^2] / 2
Initial horizontal position, Xo =0
Initial horizontal velocity, Vox = 22.3 m/s
kind of motion: uniform in the horizontal direction => X = Vox *t
You can find:
a) Height when the ball is passing the net, which is at 11.9 m from the service point.
Time when X = 11.9 m
X = Vox*t => t = X / Vox = 11.9 m / 22.3m/s = 0.5336 s
Replace that time into the vertical equation to find the height, Y:
Y = Yo - Voy*t - g*(t^2) / 2 = 2.4m - 0 - 9.8 m/s^2 * (0.5336 s)^2 / 2 = 1.0 m
Then, given that height of the net is 0.91 m, the ball will pass 0.09m over the net (9 cm).
b) How far from the net the ball will hit the ground, given that it is 11.9 m away of the service point.
From the vertical equation you can determine the flight time:
Y = Yo - g(t^2) / 2 => 0 = 2.4 - 4.9 t^2 => 4.9t^2 = 2.4 = > t^2 = 2.4 / 4.9 = 0.49 => t = √0.49 = 0.7 s
Now use that time in the vertical equation to find the X position of the ball when it hits the ground:
X = Vox *t = 22.3m/s * 0.7 s = 15.6 m
Then, subtract the position of the net to find how far away from it the ball hits the ground: 15.6 - 11.9 =3.7 m.
Applied force in an opposite direction.