# An object is thrown vertically from a height of #6 m# at # 2 m/s#. How long will it take for the object to hit the ground?

##### 1 Answer

The object reaches the ground after 1.33 s.

#### Explanation:

The convenient thing about using the equations of motion for a problem like this, is that you do not have to split the motion into an "upward" part and a "downward" part. Just as long as the acceleration is constant (it is) and you keep track of the signs on your numbers, you can do it is a single calculation.

Here it is. Use this equation:

because you do not know the final velocity of the object.

In this problem,

This is a quadratic equation! Write it in standard form

The two answers are

The first answer is the one we want. The second represents the time the object would have been on the ground if, instead of being thrown from 6 m, it had been thrown 0.92 s earlier, from the ground.