We are given the gravitational potential energy and the height of the ball and is asked in the problem to determine the mass of the ball. the formula to be followed is PE = mgh where g is the gravitational acceleration equal to 9.81 m/s^2. substituting, 58.8 J = m*9.8 m/s^2 * 30 m; m = 0.2 kg.
Answer:
<em>85.12 μAmp</em>
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Explanation:
The battery power output = 17.15 Amp-hr
If the battery is to last 23 years, we have to calculate how many hours there are in 23 years
in one year there are 24 hours x 365 day = 8760 hrs
in 23 years there are 23 x 8760 = 201480 hours
maximum current to be drawn from the battery = (17.15 Amp-hr) ÷ (201480 hours) = 85.12 x 10^-6 Amp = <em>85.12 μA</em>
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
The answer will be C because when the biker brakes, heat will be generated because of the friction
Answer:
the average acceleration due to gravity on earth is 9.8m/s2 and on moon it is 1/6 of the earths acceleration due to gravity