Answer:
B. The particles that make up material B have more mass than the
particles that make up material A.
Explanation:
The force is proportional to the product of the charges. So if either one increases, the force between them increases.
Answer:
Kristine is correct
Explanation:
this is because when an ice cube is placed into the warm water, it absorbs the heat from the water in order to melt which lowers the water's temperature.
in Eric's case, a hot cup of tea does not lose its heat because of cold hands. it varies depending on the cup whether it is a good insulator or not. also the heat can be lost through the air as well.
Answer:
8) 709.8875 J
9) The object is at 7.24375 m from the ground
10) Kinetic energy increases as the object falls.
Explanation:
We use the expression for the displacement h(t) as a function of time of an object experiencing free fall:
h(t) = hi - (g/2) t^2
hi being the initial position of the object (10m) above ground, g the acceleration of gravity (9.8 m/s^2), and t the time (in our case 0.75 seconds):
h(0.75) = 10 - 4/9 (0.75)^2 = 7.24375 m
This is the position of the 10 kg object after 0.75 seconds (answer for part 9)
Knowing this position we can calculate the potential energy of the object when it is at this height, using the formula:
U = m g h = 10kg * 9.8 (m/s^2) * 7.24375 m = 709.8875 J (answer for part 8)
Part 10)
the kinetic energy of the object increases as it gets closer to ground, since its velocity is increasing in magnitude because is being accelerated in its motion downwards.
B. a combustion reaction involves a hydrocarbon burning with oxygen gas to produce water and carbon dioxide.
C. this is an endothermic reaction since ΔH would be positive.
3. I am pretty sure it is referring to the activation energy which is a characteristic all chemical reaction have and in a combustion reaction the spark gets the reaction over the activation energy.
4. K₂O(s)+CO₂(g)⇒K₂CO₃(s)+energy
The energy level of the reactants is higher than the energy level of the products (you can see this with energy diagrams).
5. 2HgO(s)+energy⇒2Hg(l)+O₂(g)
the energy levels of the products is higher than the energy level of the reactants. (this can also be seen with energy diagrams)
