This can be seen as a trick question because heat engines can typically never be 100 percent efficient. This is due to the presence of inefficiencies such as friction and heat loss to the environment. Even the best heat engines can only go up to around 50% efficiency.
Answer:
Force applied
Explanation:
An object will remain at its state of rest unless a non zero for act on it
Then, the reaction does not have any kinetic energy
Answer:
V = 6.65 [volt]
Explanation:
First, we must calculate the power by means of the following equation, where the voltage is related to the energy produced or consumed in a given time.
![P=E/t\\P = 40/30\\P = 1.33[s]](https://tex.z-dn.net/?f=P%3DE%2Ft%5C%5CP%20%3D%2040%2F30%5C%5CP%20%3D%201.33%5Bs%5D)
Using the power we can calculate the voltage, by means of the following equation that relates the voltage to the current.
where:
V = voltage [Volts]
I = current = 200 [mA] = 0.2 [A]
![V = 1.33/0.2\\V = 6.65 [volt]](https://tex.z-dn.net/?f=V%20%3D%201.33%2F0.2%5C%5CV%20%3D%206.65%20%5Bvolt%5D)
m₁ = mass of sample of copper = m₂ = mass of sample of aluminum = 5 g
T = initial temperature of copper = initial temperature of aluminum
T₁ = final temperature of copper
T₂ = final temperature of aluminum
c₁ = specific heat of copper = 0.09 cal/g°C
c₂ = specific heat of aluminum = 0.22 cal/g°C
Since both receive same amount of heat, hence
Q₁ = Q₂
m₁ c₁ (T₁ - T) = m₂ c₂ (T₂ - T)
(5) (0.09) (T₁ - T) = (5) (0.22) (T₂ - T)
T₁ - T = (2.44) (T₂ - T)
Change in temperature of copper = (2.44) change in temperature of aluminum
hence the correct choice is
c. The copper will get hotter than the aluminum.
