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A cannon, elevated at 40 degrees is fired at a wall 300 meters away on level gro

ID: 2178117 • Letter: A

Question

A cannon, elevated at 40 degrees is fired at a wall 300 meters away on level ground, as shown in the figure. The initial speed of the cannonball is 89 m/s.

Figure: http://www.flickr.com/photos/29142812@N04/8065044348/in/photostream

a.) How long does it take for the ball to hit the wall?

b.) At what height h does the ball hit the wall?

IMPORTANT: SHOW WORK!

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I got 4.4 s for the first one and I got 252m for the second, both were marked off.

Thanks in advance!

Explanation / Answer

Time=horizontal distance/horizontal speed=300/89Cos40=4.4s

By equation of trajectory,

y=300Tan40-9.8*3002/2*892*Sec240=156.9m