Answer:
Al2O3 + 3Mg ===》 3MgO + 2Al
Explanation:
Reaction of aluminium oxide with magnesium metal would form magnesium oxide and aluminium metal.
Balancing the stoichiometric equation, the number of atoms at the reactant must be equal to the number of atoms at the product so that law of conservation of matter must hold.
Al203 + 3Mg ====》 3MgO + 2Al
2 aluminium at reactant = 2 aluminium at product
3 oxygen at reactant = 3 oxygen at product
3 magnesium at reactant = 3 magnesium at product.
When you're in an airplane that's 7 miles up off the ground, the strength of gravity plunges to only 99.6 percent of its strength all the way down on the ground.
A big heavy person, who weighs 200 pounds down at the airport, weighs only 199 pounds 4.7 ounces in a plane at the altitude of 7 miles.
Answer:
570 N
Explanation:
Draw a free body diagram on the rider. There are three forces: tension force 15° below the horizontal, drag force 30° above the horizontal, and weight downwards.
The rider is moving at constant speed, so acceleration is 0.
Sum of the forces in the x direction:
∑F = ma
F cos 30° - T cos 15° = 0
F = T cos 15° / cos 30°
Sum of the forces in the y direction:
∑F = ma
F sin 30° - W - T sin 15° = 0
W = F sin 30° - T sin 15°
Substituting:
W = (T cos 15° / cos 30°) sin 30° - T sin 15°
W = T cos 15° tan 30° - T sin 15°
W = T (cos 15° tan 30° - sin 15°)
Given T = 1900 N:
W = 1900 (cos 15° tan 30° - sin 15°)
W = 570 N
The rider weighs 570 N (which is about the same as 130 lb).
The answer is C!! 100 kilometers per hour is an average speed.