Question

A balloon is going vertically upwards at a speed of 10 ms-1 . When it was 30 m above the ground, an object is dropped from it. How long does the object take to reach the ground? (g = 10 ms-1 )​

Answer 1

t ≈ 3.65 s

Explanation:

Let the distance the object travels after leaving the balloon be x.

Using Newton's equation of motion, we have;

s = ut + ½gt²

We are given;

s = 30 m

u = -10 m/s (negative because it is an upward motion)

Thus;

30 = -10t + ½(10)t²

30 = -10t + 5t²

5t² - 10t - 30 = 0

Using quadratic formula, we have;

t ≈ 3.65 s