Question

An object is dropped from a balloon that is 100 m in the air. If the object strikes the ground at 45 m/s, how fast was the balloon moving upward when it was dropped?

Answer 1

Answer:

u=7.93 m/s

Explanation:

Given that

h= 100 m

Speed of the object when it hit the ground ,v= 45 m/s

Lets take velocity of the object when it drops from the balloon = u m/s

Lets take mass of the object = m kg

The potential energy for the object when it drop = m g h

U = m g h

U = 100 m g

From energy conservation

$U=\dfrac{1}{2}mv^2-\dfrac{1}{2}mu^2$

2 U = m (v²-u²)

2 x 100 m g =m( 45² - u²)

200 g = 45² - u²

u² = 45² - 200 x 9.81    ( take g = 9.81 m/s²)

u=7.93 m/s

Therefore the speed of the balloon will be 7.93 m/s