Final answer:
The iPhone takes approximately 3 seconds to accelerate towards the Earth from a blimp that is 70m above. The speed of the iPhone just before it hits the ground is approximately 29.43 m/s.
Step-by-step explanation:
To calculate the time it takes for the iPhone to accelerate towards the Earth, we can use the equation of motion s = ut + 0.5at^2, where s is the distance, u is the initial velocity, t is the time, and a is the acceleration. In this case, the initial velocity is 0 m/s, the distance is 70 m, and the acceleration is due to gravity, which is approximately 9.81 m/s². Plugging in these values, we get 70 = 0 + 0.5 * 9.81 * t^2. Solving for t, we find that t is approximately 3 seconds.
The speed of the iPhone just before it hits the ground can be calculated using the equation v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time. In this case, the initial velocity is 0 m/s, the acceleration is 9.81 m/s², and the time is 3 seconds. Plugging in these values, we find that the final velocity is approximately 29.43 m/s.