Help with physics?

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Best Robot EU

Senior Member

10-13-2013

Quote:
Originally Posted by YGY818 View Post
Phone a friend. (classmate)
I don't have any irl friends


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Father Zyzz

Member

10-13-2013

Quote:
Originally Posted by Best Robot EU View Post
f=ma?
Yay!
We are missing the acceleration of the boat but are given the tools to find it. Give an attempt, friend.


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Best Robot EU

Senior Member

10-13-2013

Quote:
Originally Posted by Riot Morgageddon View Post
Morgageddon tries to remember college...

Well, it's worded awkwardly, but I have to assume you go from 3 m/s at the start of your 500m and then end at 16 m/s at the end of the 500m. From this, you can make a velocity profile, use the standard kinematic equation and integrate to find the total energy expended to have the sailboat go from 3 m/s to 16 m/s over 500 meters. Then, you can equate that to an equal force applied at a single point at the start, with a magnitude and a direction, something that'll be like 1500N @ 73 degrees north of east (since you said nothing about currents or other forces acting on the sail boat).

tl;dr

Draw out the problem to start. Find your governing equations. Solve said equations.
oh
um
ok
ty morgageddon


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Spitsonkittens

Senior Member

10-13-2013

LOL. Morgageddon responds to help. What a nice guy.

Still ironic that instead of moving to off-topic he helps. Oh GD...


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Desmond Law

Senior Member

10-13-2013

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Riot Morgageddon

Player Support Tech Specialist

10-13-2013
2 of 2 Riot Posts

Morgageddon thinks to his engineering books back in his apartment.

LOL. Morgageddon responds to help. What a nice guy.

Still ironic that instead of moving to off-topic he helps. Oh GD...


I did graduate with a BS in Mechanical Engineering, this kind of stuff brings back memories of college and problem solving


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Best Robot EU

Senior Member

10-13-2013

woot i got it
ty everyone


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Samflash3

Senior Member

10-13-2013

Quote:
Originally Posted by Best Robot EU View Post
woot i got it
ty everyone
Did you use the equations of motion?


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Flennel

This user has referred a friend to League of Legends, click for more information

Senior Member

10-13-2013

Quote:
Originally Posted by Best Robot EU View Post
A 380 kg sailboat increases its speed from 3 m/s to 16 m/s while travelling 500 m at an angle of 73 north of east. Find the magnitude and direction of the net force that acts on the sailboat.

holy **** how do I even do this
First of all, this feels trolly. Especially, knowing your post history in GD.

The 73 degrees does not matter unless the problem specifically says to break down the forces to North (a Y) and East (as X) coordinate system.

Assuming the acceleration is uniform, then 500 meters is travelled on average of (3+16)/2=9.5 m/s speed over 500 meters. 500/9.5 = 52.63 seconds. Acceleration therefore is dv/s = (16-3)/(500/((3+16)/2)) = (16-3)(16+3)/(500*2) = 256-9/1000 = 0.247.

So F=380*0.247 = 93.86


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Daedalus871

Senior Member

10-13-2013

F = ma

(V^2(final)-V^2(initial))/2 = a*(distance traveled)

North of East implies that it is rotated counterclockwise 73 degrees from the x axis (East),

F(x) = Fcos(73), F(y) = Fsin(73) (from the geometry of the problem)


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