A hot air balloon is rising upward with a constant speed of 15 m/s. When the balloon is 4 m above the ground, the balloonist accidentally drops a compass over the side. What is the speed before it hits the ground? And How high above the ground is the balloon when the compass hits the ground?

1. Use v^2 = u^2 +2as[/math] to find the speed at which it hits the ground.

You have u, a and s. You can solve for v.

2. Use

It's a quadratic equation that you solve using the formula



With that, you found the time elapsed. In that time, you can find the additional distance covered by the balloon using

Then, add that s with 4 m to have the distance from the ground of the balloon.

Hope it helped! :)