Answer:
3m/s
Explanation:
Data obtained from the question include:
Initial speed (s1) = 4 m/s
Final speed (S2) = 7m/s
Change in speed (ΔS)
ΔS = s2 — s1
ΔS = 7 — 4
ΔS = 3m/s
Therefore, the change in speed is 3m/s
As the concrete has cement, gravel, crushed rocks, sand, and water of different physical state and can be separated by physical methods hence it should be called as a mixture.
As the components have significant physical boundaries which clearly identify their presence, the mixture is heterogeneous and not homogeneous.
Thus this is a concrete is a heterogeneous mixture of cement, gravel, crushed rocks, sand, and water
Percent error can be calculated by the difference of the theoretical value and the measured value divided by the theoretical value multiplied by 100 percent.
% error = 27.26 - 27.2 / 27.26 x100
% error = 0.22%
A value close to zero would mean that the measured value is more or less near the actual value.
<h2>Answer:</h2>
<u>Temperature dependency is responsible for the process that hot water freeze faster than cold water.</u>
<h2>Explanation:</h2>
The effect given above is called Mpemba Effect. According to this idea hot water freezes more quickly as compared to cold water. But until now there is no convincing explanation for this strange phenomenon. One idea is that hot containers make better thermal contact with a refrigerator and so conduct heat more efficiently because a good conductor is good fro the transfer of heat. Another idea about this effect is that warm water evaporates more quickly and since this is an endothermic process, it cools the water making it freeze more quickly.
Answer:
This question appears incomplete
Explanation:
This question appears incomplete because of the absence of options. However, hydrogen is placed in group 1 because it has just one electron in it's outermost shell (which happens to be the only shell it has) just like every other group 1A/group 1 element. While helium is placed in group 8A/group 18 because it has a completely filled outermost shell (which is also the only shell it has) just like every other element in group 8A/group 18.
