Gallium-72
Explanation:
Gallium has 31 protons, and no of protons define the atom (which element it is), that rules out Yttrium. Gallium also has the isotope Gallium-70(31+39=70), so when you add 2 neutrons you get Gallium-72.
(1) Use the formula
(energy E) = (specific heat capacity c) x (mass m) x (change in temperature T)
To raise the temperature of the water by 7 degrees Celsius, about 0.88GJ (Gigajoules) of thermal energy is needed.
(2) There are multiple reasons for the observation: Water and concrete have different specific heat capacity, namely that of water is about 4 times higher than one of concrete, so given the same amount of thermal energy, the temperature rises only about a quarter with water as compared to concrete. Another factor in the difference is that while it suffices to heat a relatively thin surface layer of the concrete (i.e., small volume) for it to feel hot to touch, heating the water involves heating a larger volume at a time due to its continuous mixing with lower layers (since it is a liquid with low viscosity).
(3) (a) Install thermal insulation around ducts to minimize thermal energy loss. (b) consider installing multiple heating zones to increase focus of heating to areas that need heating at a given time. (There are many other possible ways, these are just suggestions)
Answer:
1.97 m/s.
Explanation:
From the question,
Using the law of conservation of energy,
The energy stored in the charged plate = Kinetic energy of the mass
1/2(qV) = 1/2mv².......................... Equation 1
Where q = charge, V = voltage, m = mass, v = velocity.
make v the subject of the equation
v = √(qV/m)......................... Equation 2
Given: q = 6.5×10⁻⁶ C, V = 12000 Volts, m = 0.02 kg
Substitute these values into equation 2
v = √(6.5×10⁻⁶×12000 /0.02)
v = √3.9
v = 1.97 m/s.
Answer:
-10.267
Explanation:
Initial speed > 35 miles per hour
Final speed > 0 miles per hour
Time > 5 seconds
Answer:
10 minutes
Explanation:
Given:
Given:Speed of bus excluding stoppages =54 km/h
Speed of bus including stoppages = 45 km/h
To calculate: Minutes/per hour the bus stopped = ?
Distance covered by bus without stopping =54 km/h
Distance covered by bus with stopping =45 km/h
Due to stoppages it could
9km (54-45km) less
Time taken to cover 9 km=?
time \: taken \: = \frac{distane}{speed }timetaken=
speed
distane
Distance=9km
Speed = 54km/h.
Substituting given values on the above formula we get,
time \: taken \: = \frac{9}{54} hour = \frac{1}{6} hour \:timetaken=
54
9
hour=
6
1
hour
=10 minutes
Hence,the correct answer is 10 minutes.