Final answer:
The height of the balloon at rest is 1960 m above the ground. If the balloon was ascending at a speed of 50 m/s, the height is 960 m above the ground.
Step-by-step explanation:
Calculating the Height of the Balloon
To answer the student's two-part question, we will apply the principles of kinematics.
The acceleration due to gravity (g) is 9.8 m/s2, and we will assume that air resistance is negligible.
Part a: Balloon at Rest
The bottle is dropped from rest, so its initial velocity is 0 m/s.
The formula to calculate the height (h) in such a scenario is h = (gt2)/2, where t is the time taken to reach the ground. Plugging the values in, we get:
h = (9.8 m/s2 × (20 s)2) / 2
= 1960 m
Part b: Balloon Ascending at 50 m/s
Since the bottle is dropped from an ascending balloon, its initial velocity (u) will be -50 m/s (negative because the motion is in the opposite direction to gravity).
Using the formula h = ut + (gt2)/2, we calculate:
h = -50 m/s × 20 s + (9.8 m/s2 × (20 s)2) / 2
= -1000 m + 1960 m
= 960 m