The formula PE(Potential Energy)= mgh
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)
The sun we'll say is farthest left then the moon in the middle and then the earth farthest right
Mass of car, M=2000kg
Velocity, V=72× 5/18 =20ms¹
Apply kinematic equation of motion
v² -u² = as
0 − 20² =2a×20
a=−10ms^-2
Breaking force, F=ma=2000×10=20 kN
Apply first kinematic equation
v = u +at
