An object is thrown horizontally from the open
window of a building. If the initial speed of the
object is 20 m/s and it hits the ground 2.0 s later,
from what height was it thrown? (Neglect air
resistance and assume the ground is level.)
Initial vertical velocity = 0
formula: s = ut + (1/2)*g*t^2
s = 0 + 1/2*9.8*2^2
s = 9.8*2 = 19.6 m
The correct answer is
<span>A) 0 m
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In fact, the displacement is a vectorial quantity that corresponds to the difference between the initial and the final position of an object in motion. In this problem, the final position of the ball is equal to its initial position (because the ball returns back to where it was launched), so the displacement of the ball is zero.
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(NH4)2CO3(s) ⇄ 2NH3(g) + CO2(g) + H2O (g)
The effect that adding water (H2O) have in reaction above is that The concentration of the product would decrease, and the concentration of reactant would increase. (answer C)
<u><em>Explanation</em></u>
- If the concentration of one substance is changed, the equilibrium shift to minimize the effect of that change.
- H2O in reaction above is a product.
- Increase of water (H2O) concentration will led to the shift of equilibrium to the left ( reactant side) .The concentration of reactant increase as that of product decrease.
Assuming ideal conditions, Boyle's law says that
<em>P₁ V₁ </em>= <em>P₂</em> <em>V₂</em>
where <em>P₁ </em>and <em>V₁</em> are the initial pressure and temperature, respectively, and <em>P₂</em> and <em>V₂</em> are the final pressure and temperature.
So you have
(455 mm Hg) (56.5 m³) = (632 mm Hg) <em>V₂</em>
==> <em>V₂</em> = (455 mm Hg) (56.5 m³) / (632 mm Hg) ≈ 40.7 m³
Answer: Objective Observations
Explanation: The first step in the Scientific Method is to make objective observations. These observations are based on specific events that have already happened and can be verified by others as true or false
