Got Homework?
Connect with other students for help. It's a free community.
Here's the question you clicked on:
 0 viewing
ksaimouli
Group Title
A block rests on a horizontal surface and weighs 425 N. A force is applied to the block and has a magnitude of 142 N. The force is directed upward at an angle relative to the horizontal. The block begins to move horizontally when the angle is 60 degrees. Determine the static coefficient.
 2 years ago
 2 years ago
ksaimouli Group Title
A block rests on a horizontal surface and weighs 425 N. A force is applied to the block and has a magnitude of 142 N. The force is directed upward at an angle relative to the horizontal. The block begins to move horizontally when the angle is 60 degrees. Determine the static coefficient.
 2 years ago
 2 years ago

This Question is Closed

henpen Group TitleBest ResponseYou've already chosen the best response.1
dw:1349552917635:dw
 2 years ago

ksaimouli Group TitleBest ResponseYou've already chosen the best response.1
Correct me if I am wrong but here goes: Yea I get the x component to be 71N as well. The point at where the block is about to move is where the applied force is equal to the friction force. Friction = static coefficient * normal force I get 71 = static coefficient * 425 static coefficient = 71/425 = 0.167
 2 years ago

henpen Group TitleBest ResponseYou've already chosen the best response.1
The normal force, N\[N=425\] The force along the horizontal, Fx, is\[F_x=142\cos(\theta)\]
 2 years ago

henpen Group TitleBest ResponseYou've already chosen the best response.1
http://en.wikipedia.org/wiki/Friction#Dry_friction When it is just about to move, the force of friction equals the normal force times the coefficient of friction. So \[142 \cos(60)=71= \mu 425\]
 2 years ago

henpen Group TitleBest ResponseYou've already chosen the best response.1
So yes, you are correct.
 2 years ago

ksaimouli Group TitleBest ResponseYou've already chosen the best response.1
no but the answer is .235
 2 years ago

henpen Group TitleBest ResponseYou've already chosen the best response.1
dw:1349553164246:dw
 2 years ago

ksaimouli Group TitleBest ResponseYou've already chosen the best response.1
i know i am wrong somewhere
 2 years ago

ksaimouli Group TitleBest ResponseYou've already chosen the best response.1
answer should be .235
 2 years ago

Decart Group TitleBest ResponseYou've already chosen the best response.1
dw:1349553244013:dw
 2 years ago

ksaimouli Group TitleBest ResponseYou've already chosen the best response.1
ok how do u solve it
 2 years ago

Decart Group TitleBest ResponseYou've already chosen the best response.1
\[\sum_{F}^{?}=142\]
 2 years ago

henpen Group TitleBest ResponseYou've already chosen the best response.1
@Decart is correct I did not take into account F_y, the fact that the force's ycomponent weakens the normal force. @ksaimouli , just subtract 142sin60 from the normal force.
 2 years ago

ksaimouli Group TitleBest ResponseYou've already chosen the best response.1
i am confused
 2 years ago

henpen Group TitleBest ResponseYou've already chosen the best response.1
dw:1349553460977:dw
 2 years ago

henpen Group TitleBest ResponseYou've already chosen the best response.1
Okay you push the block at an angle. This does 2 things push the block ALONG (which is resisted by friction) and UP (opposite to gravity, so this reduces the block's force on the ground, as the force of the block DOWN is decreased, so it reduces the normal force the ground exerts on the block). It's as if you have a man pushing horizontally with force Fx and a cable with tension Fy pulling up on the block.
 2 years ago

ksaimouli Group TitleBest ResponseYou've already chosen the best response.1
what is force of friction
 2 years ago

henpen Group TitleBest ResponseYou've already chosen the best response.1
The normal force changes, so the friction changes. @Decart , I'm not sure what you're doing, but Fy is defintely using sine This gives the right answer by the way.
 2 years ago

ksaimouli Group TitleBest ResponseYou've already chosen the best response.1
instead of that can ii say 142cos60?
 2 years ago

ksaimouli Group TitleBest ResponseYou've already chosen the best response.1
i got i got ohhhhhhhh it is simple guys
 2 years ago

ksaimouli Group TitleBest ResponseYou've already chosen the best response.1
dw:1349554073776:dw
 2 years ago

ksaimouli Group TitleBest ResponseYou've already chosen the best response.1
so friction is 71 by finding the Fn=302
 2 years ago

ksaimouli Group TitleBest ResponseYou've already chosen the best response.1
dw:1349554155311:dw
 2 years ago

ksaimouli Group TitleBest ResponseYou've already chosen the best response.1
thx u for helpinggggggggggggg me
 2 years ago

ksaimouli Group TitleBest ResponseYou've already chosen the best response.1
i have only one question how did u get the equation Fn=mgfy
 2 years ago

henpen Group TitleBest ResponseYou've already chosen the best response.1
http://gyazo.com/cef28f38aa4b15271c0397dce1f96da1
 2 years ago

ksaimouli Group TitleBest ResponseYou've already chosen the best response.1
i got u thx
 2 years ago
See more questions >>>
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.