Wednesday

October 22, 2014

October 22, 2014

Posted by **Stuck** on Thursday, July 29, 2010 at 8:45pm.

I thought I would firstly find the acceleration of the hammer down the roof.

ma = Fgx

a = (9.81)(sin30) = 4.905

Using the acceleration, I found the final velocity at the roof.

Vf^2 = Vi^2 + 2ad

Vf^2 = 0 + 2(4.905)(32)

However, is the initial velocity 0?

After I found Vf, I used that as the initial velocity to find the time it would take for the hammer to fall to the ground, and then used that time to find the horizontal distance. I don't get the answer though...am I even doing this correctly?

- Physics -
**bobpursley**, Thursday, July 29, 2010 at 9:13pmYour Vf (velocity at the edge) is correct. However, now you have to break that into a horizonal velocity, and a vertical velocity.

Verticalatroofedge=sqrt (2*4.9*32)

horizontal component=sin30*sqrt( )

vertical component= cos30*sqrt( )

now you can find the time down...

32=verticalcompnent*t+1/2 g t^2 solve for t.

then, horizonal distance= vhorizontal component*t

- Physics -
**Damon**, Thursday, July 29, 2010 at 9:17pmI would use energy to get the speed at the roof edge.

(1/2) m v^2 = m g * 32 sin 30

v^2 = 9.81 * 64 (.5) = 313.9

v = 17.7 m/s which agrees with you so far

However now you have two problems, a horizontal problem and a vertical problem.

The horizontal speed is 17.7 cos 30 = 15.3 m/s and remains constant

The initial vertical speed down is 17.7 sin 30 = 8.85

so

32 = 8.85 t + .5*9.81 t^2

solve that for t

then distance horizontal = 8.85 t

**Answer this Question**

**Related Questions**

physics - A large building has an inclined roof. The length of the roof is 69.5 ...

Southern Union - A large building has an inclined roof. The length of the roof ...

trigonometry - A carpenter is building a house. He is constructing the roof. The...

Physics - A hammer slides down a roof that makes a 40.0 degree angle with the ...

two dimensional kinematics - A hammer slides down a roof of angle theta (with ...

Physics - After delivering his toys in the usual manner, Santa decides to have ...

PreCalc - A contractor plans to build an artist's studio with a roof that slopes...

Physics - You lose your footing and slide of of your roof. Fortunately, you have...

physics - a worker lays a rubber handled 0.500kg hammer down a sloped roof. it ...

Physics - We are standing at a distance d=15 m away from a house. The house wall...