Aboy throws a water ballon such that it hits his sister standing 10m away. the boy threw the water balloon at an angle of 35 degrees. how hard did he throw the balloon?

7.734 m/s

Explanation:

We have the following data:

The angle at which the water ballon was thrown

 The horizontal distance of the water ballon

The acceleration due gravity

We need to find the initial velocity at which the water ballon was thrown, and we can find it by the following equation:

(1)

Where is the total time the water ballon is on air

On the other hand, when we talk about parabolic motion (as in this situation) the water ballon reaches its maximum height just in the middle of this parabola, when and the time is half the time it takes the complete parabolic path.

So, if we use the following equation, we will find :

(2)

Isolating :

(3)

Remembering :

(4)

Substituting (4) in (1):

(5)

Isolating :

(6)

(7)

Finally:

probably not if net force is zero