# Recent content by iamwilson

1. ### Flying Buttress

Homework Statement A symmetric building has a roof sloping upward at 34.0 degrees above the horizontal on each side. A)If each side of the uniform roof weighs 1.10×10^4N , find the horizontal force that this roof exerts at the top of the wall, which tends to push out the walls...
2. ### Stuck on integration

so i did as u said, i changed them to spherical polar, z=3psin(phi), but x^2+y^2+z^2=1, i don't know how to change that to shperical polar, could you please help me. the homework is due tomorrow and i've a test on that day too！ thanks!
3. ### Stuck on integration

i also tried that way but how do i get phi though and theta
4. ### Stuck on integration

Homework Statement FInd the volume of the solid that lies within the sphere x^2 + y^2 + z^2 = 1, above the xy plane, and outside the cone z = 3 \sqrt{x^2+y^2} Homework Equations The Attempt at a Solution i tried to use rdzdrd(theta) to integrate this question but i can't get it...
5. ### Double integrate help

yes， i did, even ask my professor on how to doing it, but she only gave me the r=7+7cos(theta) but that doesn't make sense, i thought it's 14cos(theta), Dick, i completely loss, can anyone help me on this one
6. ### Polars again

Homework Statement A.Using polar coordinates, evaluate the improper integral of e^(-10(x^2+y^2))dxdy B. use part A to integrate from negative infinity to positive infinity of e^(-10x^2)dx 2. Homework Equations [/b] The Attempt at a Solution i got part A to be pi/10, but for...
7. ### Double integrate help

Homework Statement Using polar coordinates, evaluate the integral which gives the area which lies in the first quadrant below the line y=7,and between the circles x^2 + y^2 = 196 and x^2 - 14x + y^2 = 0. Homework Equations The Attempt at a Solution i tried to double integrate...
8. ### Angular acceleration of the disk as a function of time

NVM, i figured it out
9. ### Angular acceleration of the disk as a function of time

Homework Statement A disk of radius 21.0cm is free to turn about an axle perpendicular to it through its center. It has very thin but strong string wrapped around its rim, and the string is attached to a ball that is pulled tangentially away from the rim of the disk (the figure ). The pull...
10. ### Help on Physics homework

sorry, this is my first time using this website, so i don't know all the rules, but it's is extremely helpful
11. ### Rocket in space

Homework Statement If the rocket has an initial mass of 6000kg and ejects gas at a relative velocity of magnitude 2000m/s , how much gas must it eject in the first second to have an initial acceleration of 25.0m/s^2 Homework Equations v=v_exln(m_0/m) The Attempt at a Solution i...
12. ### Help on Physics homework

A rocket is fired in deep space, where gravity is negligible If the rocket has an initial mass of 6000kg and ejects gas at a relative velocity of magnitude 2000m/s , how much gas must it eject in the first second to have an initial acceleration of 25.0m/s^2 ? im stuck on this problem, can...