Answer:
7.5 m/s²
Explanation:
The following data were obtained from the question:
Initial velocity (u) = 21 m/s
Final velocity (v) = 36 m/s
Time (t) = 2 secs
Acceleration (a) =..?
The acceleration of an object is simply defined as the rate of change of velocity of the object with time. Mathematically, it is represented as:
Acceleration (a) = (final velocity (v) – initial velocity (u)) / time (t)
a = (v – u)/t
With the above formula, we can determine the acceleration of the roller coaster as follow:
a = (v – u)/t
a = (36 – 21)/2
a = 15/2
a = 7.5 m/s²
Therefore, the acceleration of the roller coaster is 7.5 m/s².
Answer:
I think is b
Explanation:
if im wrong, heres some information:
mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a medium.[1] While waves can move over long distances, the movement of the medium of transmission—the material—is limited. Therefore, the oscillating material does not move far from its initial equilibrium position. Mechanical waves transport energy. This energy propagates in the same direction as the wave. Any kind of wave (mechanical or electromagnetic) has a certain energy. Mechanical waves can be produced only in media which possess elasticity and inertia.
Answer:
The correct answer is: <em>They each partially describe the bonding in a molecule.</em>
Explanation:
Some chemical molecules cannot be described completely by using only one Lewis structure. In these cases, we can describe the molecule by drawing 2 or more Lewis structures, and the structures are called <u>resonance structures</u>. The overall molecular structure is explained by all the resonance structures together. So, they each describe the bonding in the molecule only partially.
Answer:
The percent yield of NaCl is 78.7 %
Explanation:
CuCl₂ + 2NaNO₃ → Cu(NO₃)₂ + 2NaCl
If the NaNO₃ is determined to be in excess, the limiting reagent is the chloride. We convert the mass to moles:
31 g . 1mol / 134.45g = 0.230 moles
Ratio is 1:2, so we can make a rule of three to determine the theoretical yield
1 mol of copper (II) chloride reacts to produce 2 moles of sodium chloride
Then, 0.230 moles of CuCl₂ will react to produce (0.230 .2) /1 ) = 0.461 moles of NaCl → we convert the moles to mass → 0.461 mol . 58.45 g / 1mol = 26.9 g
To find percent yield we do → (Yield produced / Theoretical yield) . 100
(21.2 g / 26.9 g) . 100 = 78.7 %
Answer:
(a) Condensation:Exothermic
(b) Sublimation: Endothermic
(c) Vaporization: Endothermic
(d) Freezing: Exothermic
Explanation:
When a phase change occurs, for example going from a liquid to a gas we need to increase the kinetic energy of the molecules to escape to the gas phase where the kinetic energy of the molecules is greater. By the contrary if we remove energy we slow down the molecules increasing their atttraction and slowing them as it occurs when the goes into the liquid state, hence this phase change is exothermic.
(a) Condensation : when the phase change is from a gas by definition we have a condensation phase chanhe. The reaction is exothermic, we need to cool the gas to condense.
(b) Sublimation: crystals of iodine disappear from an evaporating dish as they stand in a fume hood : this phase change receives the name of sublimation and it occurs when a solid goes directly to the gas phase without going through the liquid phase. We need to increase the energy of the molecules so it can go to the gas phase and the change is endothermic.
(c) Vaporization : rubbing alcohol in an open container slowly disappears: this phase change is vaporization and by difinition is when the liquid goes to the gas phase, hence its name vaporization. The change is endothermic, we need heat from the sorroundings to give the molecules of the liquid enough energy to escape into the vapor phase.
(d) Molten lava from a volcano turns into solid rock : this phase change is freezing and we need to lower the energy of the liquid by releasing it to the sorroundings, therore it is an exothermic phase change.
