Tagged Questions

The force on a body resulting from it's motion through a fluid (gas or liquid). This force is directly opposed to the direction of travel.

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Free Fall with Air Resistance

Can somebody help me understanding why when free falling the force on the vertical axis is F= -mg-kv, where k is the constant of air resistance and v the velocity? Suppose the vertical axis is ...
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Parachute jumping with air resistance

I need to write down a model for a man parachuting from a plane at a height h above the ground, having a velocity Vplane. I've had a look at many models online and they all start saying that F=ma=-kv-...
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Drag in Free Fall [duplicate]

I was recently thinking about how I might go about describing projectile motion with air reistance. The problem I encountered was that air resistance might cause some acceleration for a short period ...
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Calculate ballistics using Pejsa method (bullet physics)

I'm not sure if it was already asked, but, could someone please explain the Pejsa method of ballistics, specifically the velocity and trajectory (no energy, wind or lead etc.) (just drop drift and ...
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How much power is needed to drive two times faster?

Suppose a cyclist riding at speed $v$ decides to accelerate to speed $2v$. Does she have to generate $8$ times more power to sustain that speed? $P_1=F_dv$ If we double the speed, (it usually ...
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What is the difference between damping and friction?

What is the difference between damping and friction? Both of them slows down any moving system. So whats the conceptual difference between them?