a.

Distance of the shells expect to explode is .

Time taken by the shells to fire is .

First write the parametric equation to find the initial speed of the shell fired from the ground level.

.

Where , and .

Subustiute the values in the parametric equation.

b.

Distance between the barriers and the explosion of the shells is .

.

.

Consider .

Total distance is .

Therefore, the barriers should be placed away from the point where the fireworks are launched.

a.

Initial speed of the shell fired from the ground level is .

b.

The barriers should be placed away from the point where the fireworks are launched.