Suppose that the air resistance of parachute is directly proportional to the square of the falling speed, that is, f = kV ＾ 2, and the proportional coefficient k = 20n · s ＾ 2 / m ＾ 2 1) What do skydivers do in the air, 2) When the velocity reaches 4m / s, what is the falling acceleration? Is the first stage uniform acceleration? If so, why? Is it possible that the resistance is greater than gravity?

Suppose that the air resistance of parachute is directly proportional to the square of the falling speed, that is, f = kV ＾ 2, and the proportional coefficient k = 20n · s ＾ 2 / m ＾ 2 1) What do skydivers do in the air, 2) When the velocity reaches 4m / s, what is the falling acceleration? Is the first stage uniform acceleration? If so, why? Is it possible that the resistance is greater than gravity?

1) When the air resistance balances the total gravity of the parachute and the parachute, the balance speed (take-off height is high enough), 72 * 10 = 20 * V ^ 2 gets v = 6m / s, so the ending speed is 6m / S2