After the jumper goes faster than terminal velocity, the air resistance force is greater than the weight so that the acceleration is in the positive direction. The greatest positive acceleration ...

I used an air resistance that was proportional to the square of the velocity. Using data from wikipedia, I have a coefficient of drag that changes with the bullet speed - based on radar data.

If it fell flat, I could calculate the terminal velocity. Well, the Wikipedia page on air drag lists a coefficient of 2.1 for a smooth brick. How is an iPhone not a smooth brick?

As they speed up, the air resistance increases until the two forces are balanced, so they eventually reach a maximum speed and don’t go any faster. This is their terminal velocity.

Air resistance, on the other hand, does not depend on mass, only on the density of air, the shape of the object, and the velocity of the object (or the square of the velocity, depending on the ...

Using drizzle detectors, researchers discovered tiny raindrops falling more than 1.3 times as fast as terminal velocity, the speed at which air resistance cancels out gravitational pull.

It will be traveling much slower than when it was first fired, as its terminal velocity (due to air resistance) is far lower than the initial muzzle speed.

Hatcher calculated that his .30-caliber rifle bullets reached terminal velocity—the speed at which air resistance balances the accelerating force of gravity—at 300 feet per second.

That means its downward velocity increased until the upward force of air resistance, also known as drag, “balanced the downward force of gravity (the iPhone's weight) so that the iPhone stopped ...