Hello, Cathaloc2!

Quote:

(A) A projectile is launched horizontally out to sea

with an initial velocity of 98m/s from the top of a vertical cliff 78.4 m high.

(B) The angle of the launch is now raised to 30° above the horizontal.

You need the projectile formulas:

. .

. .

where: .

We are given: .

The equations are:

. .

. .

Quote:

(i) What is the time taken to reach the sea?

When is ?

We have: .

Quadratic Formula: .

The positive root is: .

Quote:

(ii) How far from the base of the cliff will it hit the sea?

Quote:

(iii) How long will it take to reach its greatest height above the point of launch?

The height function, , is a down-opening parabola.

. . Its maximum is at its *vertex*: .

We have: .

Quote:

(iv) What is the greatest height above the point of launch?