Explanation:
I remember that notation! The expression
is the 1st law of thermodynamics and it refers to the heat supplied to the system dQ which is also a change in its internal energy dU. The first term is the <u>partial</u> derivative of the internal energy U with respect to temperature T while the volume V is kept constant, as denoted by the subscript V. The 2nd term is similar but this time, temperature is kept constant while its volume partial derivative is being taken.
Ah, memories!
Answer:
The two types of energy possessed by the roller coaster are:
- Potential energy: it is the energy possessed by the roller coaster due to its position. It is calculated as
where
m is the mass of the roller coaster
g is the acceleration due to gravity
h is the height of the roller coaster relative to the ground
- KInetic energy: it is the energy possessed by the roller coaster due to its motion. It is calculated as
where
v is the speed of the roller coaster
Moreover, according to the law of conservation of energy, the total mechanical energy of the roller coaster (the sum of potential+kinetic energy) is constant during the motion:
This implies that:
- When PE increases (because h increases), KE decreases (because v decreases)
- When PE decreases (because h decreases), KE increases (because v increases)
Now we can apply these conclusions to the motion of the roller coaster:
- When it moves from A to B, potential energy is converted into kinetic energy, so PE decreases and KE increases
- When it moves from B to C, kinetic energy is converted into potential energy, so PE increases and KE decreases
- When it moves from C to D, potential energy is converted into kinetic energy, so PE decreases and KE increases
- When it moves from D to E, kinetic energy is converted into potential energy, so PE increases and KE decreases