What word describes the position in the moon's elliptical orbit when it is closest to Earth?
1 answer:
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Hey! I empathize with you, as I just started the energy unit in physics as well!
Alright, lets list what we know, and which equation(s) we need.
PE = Gravitational Potential Energy
m = mass
g = gravity (9.8 m/s^2)
h = height
Guess what?
We need to find the height!
Lets make this more organized:
Known:
m = 40 kg
PE = 14000
g = 9.8 m/s^2
Unknown:
h = ?
================================
Now, if we take a look at the equation PEg = mgh, you will see that we have everything besides the height! So lets solve for the height by substituting in for the variables we know:
14000 J = 40 kg * (9.8 m/s^2) * h
40 * 9.8 = 392
14000 J = 392 * h
14000/392 = h
35.71 m = h
There we go! If you simply list what you know and don't know, you will find the equation you need to solve the problem.
Have a great day and good luck!
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