Answer:
Exothermic Reaction
Explanation:
<u>ENDOTHERMIC REACTION</u>: A chemical reaction is considered endothermic if the energy is absorbed during the reaction. In other words, if the energy is required by the reactants to proceed with the reaction, then the reaction is endothermic.
The value of enthalpy change ΔH is positive in such reactions showing intake of energy.
<u>EXOTHERMIC REACTION</u>: A chemical reaction is considered exothermic if the energy is released during the reaction. In other words, if the energy is produced as a product of the reaction, then the reaction is exothermic.
The value of enthalpy change ΔH is negative in such reactions showing the release of energy.
Since, the value of ΔH = -125 KJ, is negative for the given reaction.
Therefore, it would be considered as <u>Exothermic Reaction.</u>
Answer: The frequency heard will be f = 275.675Hz
Explanation: When an object emitting sound is moving, it occurs a phenomenon called Doppler shift or Doppler effect. What happens is that the sound gets higher when the moving object comes closer the observer and becomes lower after it passes, This change is due to the quantity of waves that passes through an area in an unit of time.
The formula to calculate the Doppler effect is as follows
f = (
) · f₀
f is the observed frequency;
c is the speed of sound;
Vs is velocity of the source;
f₀ is the emitted frequency of source;
Substituting and calculating,
f = 
· 300
f = 275.675 Hz
Thus, the frequency heard by the police officer is 275.675Hz.
That's a formula that shows the relationship between three quantities ...
weight, mass, and acceleration. If you know any two of them, then you
can use this formula to find the one you don't know.
Examples:
==> I have a rock with 2 kilograms of mass.
The gravitational acceleration on Earth is 9.8 m/s² .
How much does my rock weigh on Earth ?
Weight = (mass) x (grav acceleration)
= (2 kg) x (9.8 m/s²)
= 19.6 newtons
(about 4.41 pounds)
==> My brother weighs 770 newtons (about 173 pounds) on Earth.
What is his mass ?
Weight = (mass) x (grav acceleration)
770 newtons = (mass) x (9.8 m/s²)
Divide each side
by 9.8 m/s²: 770 newtons / 9.8 m/s² = mass
78.57 kilograms = mass
==> When I went to the Moon, I took along my 2-kilogram rock.
I weighed my rock on the Moon.
It weighs 3.25 newtons (about 0.73 pound) there.
What is the gravitational acceleration on the Moon ?
Weight = (mass) x (grav acceleration)
3.25 newtons = (2 kg) x (acceleration)
Divide each side
by 2 kilograms: (3.25 newtons)/(2 kg) = acceleration
1.63 m/s² = grav acceleration on the Moon
It would be on the top of the HR diagram, specifically, the top right.
