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    Transformation of Stress (Mech. Materials)

    Homework Statement Question is attached Homework Equations σ(x) = 0 σ(y)= P/A t(xy)= Tc/j The Attempt at a Solution I know how to do the stress transformation, but my only issue is noticing why σ(x)= 0, I cant see it, can someone help me.
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    Electric potential

    Homework Statement As an electron moves from a high potential to a low potential, its electric potential energy? a) increases b) remains the same c) decreases Homework Equations we know that V=U q0 the electric potential = potential energy times the charge. The...
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    Equilibrium of rigid bodies

    Homework Statement Determine the reaction at C. Homework Equations The Attempt at a Solution i know i have to take the moment about line DB and thus resulting in ƩM(DB)= λ(DA X F) + λ(DC X RC) =0 where λ = DB/ DB however the book solved it differently. they instead do...
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    Statics- equilibrium of rigid bodies

    Homework Statement An opening in a floor is covered by a 1×1.2-m sheet of plywood of mass 18 kg. The sheet is hinged at A and B and is maintained in a position slightly above the floor by a small block C. Determine the vertical component of the reaction (a) at A, (b) at B, (c) at C. Homework...
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    Comp Sci C++- while-loop

    I got it and yes, there's no need why to have count there!
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    Comp Sci C++- while-loop

    I did write the whole code and declared all my variables. i just didnt want to post it fully here for some reason or the other. I apologize. here is the whole code. #include<iostream> using namespace std; int main() { int count; int num; int x; count=1...
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    Comp Sci C++- while-loop

    C++-- while-loop Homework Statement calculate the 3 largest number of a sequence Homework Equations you ask the user to input a sequence of numbers, and enter the value 0 to stop entering numbers. c++ The Attempt at a Solution i managed to calculate the the maximum of the series of...
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    Net Electric field

    Homework Statement Figure 22-7a shows three particles with charges q1= +2Q, q2=-2Q, and q3 = -4Q, each a distance d from the origin. What net electric field E is produced at the origin? Homework Equations E=q/r^2* 1/(4∏ε0) The Attempt at a Solution So i calculated the of each particles...
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    How would I integrate?

    omg! i knowwwwwwwwwwwwwwwwww! i did it. that was so stupid of me. thank you.
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    How would I integrate?

    Homework Statement integrate 2t^(2)/(1+t^2)^(2) Homework Equations trig sub 1+tan^2(x)= sec^2(x) The Attempt at a Solution the attempted solution is attached.
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    Linear momentum

    Well guys! thank you either way!
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    Linear momentum

    And since there are no external forces acting on it, then momentum is conserved. so, we have to finish with what we started. if there was a external forces, such as in a rocket thrust problem, then we will have to involve impulse, in order to calculate the the Vf of the rocket, right?
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    Linear momentum

    @Rude man, im confused. so in general, M(total) *V(initial)= M(train)*V(final train) + m(of sand)* velocity( throughout the 30 mins) which gives me vf=20m/s. which is sort of weird, since is the same velocity we started with. Is it okay to think of it this way; that in order to have...
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    Linear momentum

    It is an example question from old quizzes. why? the problem doesnt make sense? can someone help me? so would it be (100,000)(20)= (85,000)(vf) +(15,000)(20)? because the sand that is falling out, has the same speed of the cart throughout the 30 mins
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    Linear momentum

    Homework Statement Im not sure if I did this problem correctly, can someone please reassure me?! Homework Equations Conservation of Linear momentum pf=pi m1v1=m2v2 The Attempt at a Solution M(initial)=100,000 kg M(final)= 100,000kg-15,000kg= 85,000kg V(initial)=20.0m/s V(final)=...
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    Angular Momentum

    Homework Statement I am just confused about Angular momentum. Homework Equations KE(rotational)= 1/2Iw^2 Angular momentum= Iw The Attempt at a Solution Why can I do the change in KE rotational to calculate the her final angular velocity in 3 revs? very confused!! :( both equations relate...
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    Static Equilibrium and a wheel

    Thank you so much for reassuring me. I got the correct answer. the lever arm for force mg is (2rh-h^2))^1/2 and the lever arm for force F is (r-h) Thus, the sum of all torques Ʃτ= τF-τmg= 0 => τF=τmg = F(h-r)=mg(2hr-h^2)^1/2 F= [mg(2hr-h^2)^1/2]/(r-h) Thanks!!!!!!!!!!!!!!!!
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    Center of mass homework help

    Yes, I have. so you're telling me to take the triple integral? but we dont have the density.
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    Static Equilibrium and a wheel

    Why are we making the pivot point at the top of the circle, wouldnt it make more sense to put it at the corner since we dont know the friction giving by the corner? because if we put the pivot point at the corner we would just need to calculate the torques with respect to the corner. We have...
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    Static Equilibrium and a wheel

    Homework Statement what magnitude of force applied horizontally at the axle of the wheel is necessary to wheel over an obstacle of height h = 0.108 m? The wheel's radius is r = 0.698 m and its mass is m = 1.71 kg. Homework Equations I know that in order to have a static equilibrium we...
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    Center of mass homework help

    No. at first i thought we just had to take the position of each side and multiply it by the mass. but according to the book, we first had to find center of mass of the sides. Whats the appropriate way of solving these kinds of problems? because i would really like to have a good overall idea on...
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    Center of mass homework help

    Homework Statement Three uniform thin rods, each of length L = 22 cm, form an inverted U. The vertical cords each have a mass of 14 grams. The horizontal rod has a mass of 42 grams. What are the x coordinate and y coordinate of the system's center of mass? Homework Equations xcom=...
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    Conservation of Energy, pendulum problem

    but isnt height= r(1-cosθ). where r=length of the cord?
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    Conservation of Energy, pendulum problem

    Im sorry, I dont understand, Im bit more confused than i was before. Would you please elaborate a bit more? how do you the height above is that?
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    Conservation of Energy, pendulum problem

    Homework Statement To form a pendulum, a 0.092 kg ball is attached to one end of a rod of length 0.62 m and negligible mass, and the other end of the rod is mounted on a pivot. The rod is rotated until it is straight up, and then it is released from rest so that it swings down around the...
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    Relative velocity

    so if i initially calculated that v1= 9.8 and v2= 0.2 their opposite signs would be -9.8 and -0.2 and when applied to the equation lv2-v1l = l -0.2+ 9.8l is still 9.6 m/s :-/ and for some reason the professor uses, v(f) = vi-gt why is he subtracting gravitational force * time...
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    Relative velocity

    Homework Statement Ball 1 is dropped from rest at a height of 10m above the ground. at the same time, ball 2 is thrown straight upward from ground level with an initial speed of 10m/s. Homework Equations find the relative velocity of the balls when they pass each other at t=1...
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    Find a vector function that represents the curve of intersection of the two surfaces

    Homework Statement Find a vector function that represents the curve of intersection of the two surfaces: The cone z = sqrt( x^2 + y^2) and the plane z = 1+y. Homework Equations z = sqrt( x^2 + y^2) and the plane z = 1+y. The Attempt at a Solution This problem can be solved as...
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    Find the centroid of the solid in part (a).

    hahaha!I fell so dumb now. Making very stupid mistakes. thanks for output!
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