Answer:

Explanation:
Given data
Distance d=7.00 ft= 7*(1/3.281) =2.1336m
Initial velocity vi=0m/s
To find
Final velocity
Solution
From Kinematic equation we know that:

Explanation:
Reactants ⇒ product + heat (exothermic reaction) ....(1)
We have given that the reaction is exothermic, so the heat is rejected from the reaction. We know that heat is the form of energy.
From equation (1)
from the given equation we can see that reactants have more energy than products.
So the reactants have higher potential energy in comparison to the products.
Answer:
the mass of water is 0.3 Kg
Explanation:
since the container is well-insulated, the heat released by the copper is absorbed by the water , therefore:
Q water + Q copper = Q surroundings =0 (insulated)
Q water = - Q copper
since Q = m * c * ( T eq - Ti ) , where m = mass, c = specific heat, T eq = equilibrium temperature and Ti = initial temperature
and denoting w as water and co as copper :
m w * c w * (T eq - Tiw) = - m co * c co * (T eq - Ti co) = m co * c co * (T co - Ti eq)
m w = m co * c co * (T co - Ti eq) / [ c w * (T eq - Tiw) ]
We take the specific heat of water as c= 1 cal/g °C = 4.186 J/g °C . Also the specific heat of copper can be found in tables → at 25°C c co = 0.385 J/g°C
if we assume that both specific heats do not change during the process (or the change is insignificant)
m w = m co * c co * (T eq - Ti co) / [ c w * (T eq - Tiw) ]
m w= 1.80 kg * 0.385 J/g°C ( 150°C - 70°C) /( 4.186 J/g°C ( 70°C- 27°C))
m w= 0.3 kg
Answer:
far from the speaker the intensity drops to 85 dB.
Explanation:
In the equation for the Decibel scale

The ratio of the intensities can be written as


And since

and
,

meaning

Putting this into equation (1), we get:

Now, if the intensity is 100 dB when the distance is 5 meters, we have:


by taking both sides to the exponent:


Now equation (2) becomes

when the intensity level is 85 dB we have


take both sides to exponents and we get:




Thus,
far from the speaker the intensity drops to 85 dB.
Negative celestial declinations are all positions in the sky that are directly over south surface latitudes.
Sirius is SOUTH of the celestial equator.
During the course of a year, it traces a circular path directly over the parallel of 16° South latitude, taking it over Peru, La Paz in Bolivia, St. Helena island in the Atlantic, Namibia, Angola, Zambia, Mozambique, Malawi, Madagascar, Australia, French Polynesia, American Samoa, and the Pacific Ocean.