A bag of ballast is accidentally dropped from a balloon which is stationary at an altitude of 4900m. How long does it take for the bag to hit the ground?

2 Answers
Mar 5, 2018

31.6 s

Explanation:

A good equation to know for calculating time of falls due to gravity alone is:

h=12gt2t=2hg

Here, we can use h=4900 m. There is no gravity mentioned, so I will simply use 9.8 m/s2.

t=(2)(4900)9.8=31.6 s

Use the equations of motion to answer the question.

Explanation:

It is given that balloon is stationary at height (s)=4900 m. The initial velocity (u)=0 m/s.

As it falls in the downward direction, it accelerates with an acceleration of g=9.81m/s2 (for simple calculations, g=9.8 m/s2)

So

4900=0t+12gt2

On solving

t=249009.8

t=1000 s