Recent content by Jackson Smith

Here is another point: If in the equation PE = m*g*h, g is independent of thrust, then the KE you calculate from the height would also need to be independent of the thrust. We KNOW that is not true by watching the SpaceX booster rockets land. (They did not crash land; they landed very softly.)...

Actually, if you review the initial scenario, the requirement is not that thrust remain constant, but that it BALANCE gravity. So, the rocket in the middle of nowhere would need minuscule thrust (gravity never goes to zero, at least theoretically). The energy from thrust is consumed in...

The thrust is used to offset (balance) the force of gravity. From V = V0 + a*t, we know that constant velocity will result when thrust = gravity since acceleration will then be ZERO.

So, please help me understand how the PE is created, keeping in mind the equation V = V0 + a*t. If thrust = gravity, this equation results in constant velocity, right? And constant velocity is the scenario we have with our rocket. If it have constant velocity with thrust = gravity, where does...

Agree; as long as the velocity is constant, momentum will also be constant. Perhaps you were thinking of constant ACCELERATION? Now I WOULD prefer that the constant velocity also be a LOW velocity! :)

First, there need be no additional force, assuming we started with an existing velocity (say 100 M/s) when thrust was initiated to balance gravity. But based on V = V0 + a*t, velocity cannot change when thrust = gravity since the "a" when be zero. So from where would we get PE? I also can't...

I don't see a change in PE or any PE at all when we have constant velocity. In that case, thrust must equal gravity. So, to calculate PE, we have PE = m*g*h. What is the Net "g" we would use in this equation? Gravity less thrust = ZERO, so PE = 0. We have constant velocity (based on the...

I don't see how there is ANY PE change or indeed, any PE at all because at constant velocity, thrust = gravity. Any existing velocity, UP or DOWN, remains. In addition, PE = m*g*h. If thrust = gravity, isn't the (Net) g in that formula ZERO?

Could someone then please explain this: V = V0 + a*t. Therefore, when thrust = gravity, (Net "a" will be zero), V will be constant (V = V0). So, assuming we have thrust = gravity and no other forces (launch in a vacuum), how do we generate PE as the object ascends to a higher altitude without...

I would like confirmation of this concept of PE creation.

Generally, a change in altitude within a gravitational field is said to increase or decrease PE. I posit that the change in PE never occurs UNTIL there is a change in KE. Thus, in the case of an object with a constant velocity UP, there is no gain in PE until the instant that the thrust no...