# Question #afdf8

##### 1 Answer

The answer is **b)** *65 m/s*.

#### Explanation:

Here's how you should approach this problem.

You know that your ball is projected *upwards* at an initial velocity which we'll call

You also know that the distance the ball covered in its **twice** the distance it covered in its

Since the ball is projected upwards, this difference between the distances makes sense because the ball is moving *against gravity*, which implies that it's slowing down.

To get the distance the ball travelled in its **4 seconds** of flight and subtract this distance from the distance it covered after **5 seconds** of flight.

**SIDE NOTE** *I'll skip adding the units in order to keep the text clean*.

The distance it covered in its

Do the same to get the distance covered in its

Therefore,

Now use the fact that