Posted by **Tram** on Tuesday, November 12, 2013 at 2:02am.

one of the main battery of cannons protecting the entrance to San Francisco Bay were able t horizontally propel 7.3 kg cannon balls with an average speed of 26.2m/s. if the height of the cannon emplacement were 112m above San Francisco Bay,

a. how far from the cannon's muzzle (end of cannon where cannon ball exits) would the cannon ball land?

b. at what would the cannon need to be set so as to land half the distance?

My answer: a. 124m . b. 151 degrees

Are my answers correct??

- physic--help --- -
**Steve**, Tuesday, November 12, 2013 at 4:29am
how long does it take to fall 112m?

4.9t^2 = 112

t = 4.78 seconds

horizontal distance traveled is

4.78s * 26.2m/s = 125.26m

Rounding could account for the difference in our answers. I assume your 151° fits the equation, but it seems a bit odd to be firing backwards. Look for an acute angle that will give the same answer.

- physic--help --- -
**Tram**, Tuesday, November 12, 2013 at 9:03am
Where is 4.9 come from?

- physic--help --- -
**Tram**, Tuesday, November 12, 2013 at 9:16am
I got it , thank you !

## Answer this Question

## Related Questions

- physics - An airplane flies from Boston to San Francisco (a distance of 5000 km...
- physics - Two identical cannons fire cannonballs horizontally with the same ...
- physics - A railway flat car is rushing along a level frictionless track at a ...
- physics - A railway flat car is rushing along a level frictionless track at a ...
- science - You are somewhere in the middle of the country and a satellite that is...
- Physical Sciene - A cannon is fired horizontally from a top of a 15-m platform. ...
- AP Physics - Momentum One of those Civil War cannons is fired. The Cannon has a ...
- Physic - Water enters a horizontal pipe with a rectangular cross section at a ...
- physics - A 500-kg cannon and a supply of 80 cannon balls, each with a mass of ...
- Algebra 1 - A scale model of the Golden Gate Bridge in San Francisco Bay has a ...

More Related Questions