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elegysix
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Yes, it does if you neglect the KE of the exhaust. See: https://www.physicsforums.com/showthread.php?t=199087SystemTheory said:Initial velocity does not impact the change in kinetic energy
SystemTheory said:Start with the definition of the change in kinetic energy:
delta-KE = KE2 - KE1
Solve for KE2:
KE2 = delta-KE + KE1
Expand the equation and solve.
The change in velocity does not depend on the initial velocity, but KE is not a linear function of velocity, it is quadratic in velocity. So, if you differentiate KE wrt velocity you get the following relationship:SystemTheory said:Since the change in velocity does not depend on the initial velocity, the change in kinetic energy cannot depend on the initial velocity.
Yes, for a given force the power does depend on the velocity as you have stated, and I think that is indeed helpful to point out!SystemTheory said:I also notice now that the starting power of the force PI = F*vI must be greater for a greater initial velocity.
Since energy is the area under the power-time curve, it obviously takes more power and energy to accelerate the body by the same net velocity change when the force is applied at a greater initial velocity.
Hope that last comment adds some insight and does not contribute more confusion!
Remember, the conservation of energy only applies to a "closed" or "isolated" system. You determine if your system is closed by looking to see if any external forces are acting on it. So, (neglecting gravity) we see that there is an external force on the apple, so the apple is not an isolated system and the apple's energy is not conserved.elegysix said:You might say I need to do a calculation for the change in kinetic energy of the train, but, the only thing which is in contact with the apple core is your hand - so it must be that the change in the kinetic energy of the train system is from your hand tossing the apple.
That is correct.elegysix said:On a side note, if velocity has components in three dimensions, then kinetic energy is given by KE=1/2m(Vx^2+Vy^2+Vz^2), and is equipotential for R^2=Vx^2+Vy^2+Vz^2. this means that the velocity can change direction without changing the kinetic energy, which would mean without doing work
Kinetic energy is the energy an object possesses due to its motion. It is dependent on the object's mass and velocity.
The formula for kinetic energy is KE = 1/2 * m * v^2, where m is the mass of the object and v is its velocity.
Initial velocity is a crucial factor in determining an object's kinetic energy. The higher the initial velocity, the greater the kinetic energy, and vice versa.
Kinetic energy and potential energy are two forms of energy that an object can possess. Kinetic energy is the energy of motion, while potential energy is the energy an object has due to its position or state. They are interconvertible, meaning that an object can have both types of energy at the same time.
According to the law of conservation of energy, energy cannot be created or destroyed. Therefore, kinetic energy is conserved and can only be transferred or converted into other forms of energy.