Velocity and Loss in Energy onedimensional

In summary, a 15kg object is released from a height of 11.58m and experiences a loss of 320J in energy. Using the equations for gravitational potential energy and kinetic energy, the object's velocity as it enters the container can be calculated to be 13.58 m/s. There may be discrepancies in the answer due to potential friction being involved in the energy loss.
  • #1
Nuingaer
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Homework Statement


If a 15kg object is released from a height of 11.58m and the objects loss in energy is 302 J, determine its velocity as it enters the container (object is being dropped straight down into a container)
Assume g = 9.8m/s^2
m(object) = 15kg = w(object) = 147N
s = 11.58m
ΔE = -320 J

Homework Equations


Had no idea. But the ones i know that i thought could apply:
ΔKE = KE(final) - KE(initial)
KE = 1/2 * mv^2
GPE = mgh
v^2 = u^2 + 2as

The Attempt at a Solution


Okay, I had no idea how to do this, but i tried to work out as many things as i can then mash em together to get an answer :p

GPE = mgh
=15*9.8*11.58
=1702.26

Then i thought; well if the loss in energy is 320 J then i could take that from the original GPE
1702.26 - 320 = 1382.26 J

and now i could work out the new height by subbing it back in
1382.26 = 15*9.8*h
h=9.403m

And here is where it gets iffy... they say the velocity when it enters the container, but the container isn't at 9.403m its at 0...right? that's what i got from the question anyway. Therefore how did they only lose 320N? So I assumed that I could say its KINETIC energy is the 1382.26 J, and the height of the container is the difference because they say when it "enters".
Therefore..
KE = 1/2 * m * v^2
1382.26 = 1/2 * 15 * v^2
2764.52 = 15 * v^2
v^2 = 184.30
v = 13.58 m/s

We don't have the answer to this question yet, but *a lot* of other people got 13.66m/s as the answer... so since i had no idea how to do this question and no basis to support whether I am right or not, could someone help me out and either point out where i went wrong or if I'm right? thank you!
 
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  • #2
I think they mean by lose of energy that it's due to friction, because when dropping an object from a certain hight the object does't lose energy but the energy is converted from potential to kinetic, and so when the question states that there there was loss in energy i think its due to friction(i might be wrong i don't know). If this is the case then i think you should do this:
Energy (at h=11.58 )-Energy lost=1702.26-320=1382.26
Ek=1/2*mv^2
v=13.57m/s
in this case you take the barrol at hight 0.
 

FAQ: Velocity and Loss in Energy onedimensional

1. What is velocity?

Velocity is a physical quantity that describes the rate of change of an object's position. It is a vector quantity, meaning it has both magnitude and direction.

2. How is velocity different from speed?

Velocity and speed are often used interchangeably, but they are actually two different quantities. Speed is a scalar quantity that only describes the magnitude of an object's motion, while velocity also includes the direction of motion.

3. What is one-dimensional motion?

One-dimensional motion refers to motion that occurs along a single axis, such as a straight line. This type of motion can be described using only one coordinate, typically distance or displacement.

4. What is loss in energy in one-dimensional motion?

Loss in energy in one-dimensional motion refers to the decrease in an object's total energy due to factors such as friction or air resistance. This loss of energy can result in a decrease in velocity or speed.

5. How does velocity affect loss in energy in one-dimensional motion?

The velocity of an object can impact the amount of energy lost in one-dimensional motion. For example, the faster an object is moving, the more energy it may lose due to friction or air resistance. This can result in a decrease in the object's velocity over time.

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