Answer: When the fluid cools, the kinetic energy of the molecules decreases. this causes the molecules to slow down and move closer together, the density of the fluid increases and the fluid sinks
Explanation: Just took the test & it gave the answer or sample response.
The answer must be a mass x velocity
One thing you should notice. It is kind of weird. Ke has no direction so that fact that it has velocities associated with it does not matter. It becomes a scaler (something measured by amount alone).
General Formula
Ke = 1/2 m v^2
Formula for this problem
Ke = 1/2 m (v2)^2 - 1/2 m (v1)^2
Givens
m = 1200 kg
v2 = 100 km/hr = 100 km/h * [1 hour / 3600 sec] * [1000 m/ 1km] = 27.8 m/s
v1 = 50 km / hr = 13.9 m/s
Substitution and work.
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delta Ke = 1/2 1200 (27.8)^2 - 1/2 1200 (13.9)^2
delta Ke = 463704 - 115926
delta Ke = 34778 Joules
delta Ke = 34.8 kJ
The change is 34.8 kJ which means that the vehicle gains 34.8 kJ
<span>D. sugar changes from white to a light amber color
We're looking for a chemical change. So let's examine the options and see what happening with them.
A. adding cream and milk to the mixture
She's just making a mixture here. No unexpected reactions or changes happen as she adds the cream and milk. So this is the wrong answer.
B. mixing the sugar with water
Dissolving the sugar in water. Once again, nothing unusual happens and if she were to evaporate the water, she'd be left with the original sugar. So this is the wrong answer.
C. melting the sugar
Just starting a simple phase change. Once again, no the right answer.
D. sugar changes from white to a light amber color
She's melted the sugar and has a clear fluid. As she continued to heat this fluid, it suddenly turns light amber. She has made a permanent change to the substance that she can't undo by simply physical means. She has converted part of the sugar into caramel. So a chemical change has happened here.</span>
