# A cannon fires a cannonball at an angle of 45° with an initial velocity of 75 m/s off a cliff that is 150 m high?

What is the max height that the cannonball reaches?

What is the total time the cannonball is in the air?

What is the total distance the cannonball travels along the horizontal?

### 1 Answer

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- Wayne DeguManLv 72 months ago
Using v² = u² + 2as we have:

0 = (75sin45)² - 2gh

so, h = (75sin45)²/2g => 143.5 metres above point of projection.

i.e. 293.5 metres above ground

h(t) = -4.9t² + 75tsin45 + 150

The cannonball hits the ground when h(t) = -150 so,

4.9t² - 75tsin45 - 300 = 0

so, t = 14.9 seconds

Horizontal distance is 75cos45 x 14.9 => 791.5 metres

:)>

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