# An object is thrown vertically from a height of #15 m# at # 6 m/s#. How long will it take for the object to hit the ground?

##### 2 Answers

#### Answer:

2.4 seconds

#### Explanation:

If

Velocity of object when it hits the ground is

If

Total time taken

#### Answer:

The time is about 2.5 s.

#### Explanation:

Compared to your first answer, this is an alternate method of solving.

I will choose to have up be the positive direction. Use the kinematic (suvat) formula

where

#s = -15 m# because it will hit the ground -*below*the point it was thrown from#u = 6 m/s# positive because it was thrown up#a = -g = -9.8 m/s^2# .

Now, plugging in the data and solving for t

Adjust so that all 3 are on one side and zero is on the other (preparing for use of the quadratic equation)

The - part of the

I hope this helps,

Steve