00:01
Hello everyone, we need to find the mass mx, m y, x bar and y bar of the given lamina.
00:19
So we are given with the equation y is equal to minus 8x plus 3 where y is equal to x by 2 and x is equal to 0 so also we are given with the density row of x comma y is equal to 3 times of x plus y.
00:43
So let us equate this y is equal to minus 8x plus 3 and substitute x by 2 for y.
00:52
We would get minus 8x plus 3 is equal to x by 2 or we get minus 16 x plus 6 is equal to x.
01:05
From this we obtain 6 is equal to 17x or this is nothing but x is equal to 6 by 17.
01:14
So let us first compute the mass which is given by the formula.
01:19
Mass is equal to double integral over r row of x comma y, d y, d x.
01:29
So let us substitute the limits, that is, mass is equal to integral 0 to 6 by 17, integral x by 2 to minus 8x plus 3, 3 times x plus y, d, dx.
01:52
So simplifying this, we obtain integral 0 to 6 by 17, 3xyxy, plus 3xy plus 3y plus 3y, plus 3y, and x.
02:01
Square by 2 with respect to the limits x by 2 to minus 8x plus 3 dx.
02:11
So evaluating this integral, the value of mass will be approximately equal to 1 .8685.
02:22
Now we need to compute the mx value, that is m .x is equal to double integral over r.
02:35
Row of x comma y y d y d x so the limits will be same as we have computed for mass so this will be equal to integral 0 to 6 by 17 integral x by 2 to minus 8x plus 3 3 times x plus y into y d y d y d x so similar manner we will evaluate the that is integral 0 to 6 by 17 integral x by 2 to minus 8x plus 3 xy plus 3y plus 3y square dy d x simplifying further we would get integral 0 to 6 by 17 3xxy xy square by 2 plus 3y y square by 2 plus 3y cube by 3 with respect to the limits x by 2 to minus 8x plus 3 d x.
03:50
So evaluating this entire integral we would get the value of mx to be approximately equal to 2 .6874...