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Problems in Mathematical Analysis.pdf - pwp.net.ipl.pt

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&?c. 12] Apply<strong>in</strong>g Def<strong>in</strong>ite Integrals to Solution of Physical <strong>Problems</strong> 173<br />

1741. F<strong>in</strong>d the moment of <strong>in</strong>ertia of a circle of radius a about<br />

its diarneler.<br />

1742. F<strong>in</strong>d the moments of <strong>in</strong>ertia of a rectangle with sides<br />

a and b about its sides.<br />

1743. F<strong>in</strong>d the moment of <strong>in</strong>ertia of a right parabolic segment<br />

with base 26 and altitude ft about its axis of symmetry.<br />

1744. F<strong>in</strong>d the moments of <strong>in</strong>ertia of the area of the ellipse<br />

JC 2<br />

U 2<br />

^ + ^=1 about its pr<strong>in</strong>cipal axes.<br />

1745**. F<strong>in</strong>d the polar moment of <strong>in</strong>ertia of a circular r<strong>in</strong>g<br />

with radii and<br />

R^ R t (R } that is, the moment of <strong>in</strong>ertia<br />

about the axis pass<strong>in</strong>g through the centre of the r<strong>in</strong>g and perpendicular<br />

to its plane.<br />

1746**. F<strong>in</strong>d the moment of <strong>in</strong>ertia of a homogeneous right<br />

circular cone with base radius R and altitude H about its axis.<br />

1747**. F<strong>in</strong>d the moment of <strong>in</strong>ertia of a homogeneous sphere<br />

of radius a and of mass M about its diameter.<br />

1748. F<strong>in</strong>d the surlace and volume of a torus obta<strong>in</strong>ed by<br />

rotat<strong>in</strong>g a circle of radius a about an axis ly<strong>in</strong>g <strong>in</strong> its plane<br />

and at a distance b (b>a) from its centre.<br />

1749. a) Determ<strong>in</strong>e the position of the centre of gravity of<br />

2 2 t<br />

an arc of the astroid xT T = -\-i/ a* ly<strong>in</strong>g<br />

b)<br />

<strong>in</strong> the first quadrant.<br />

F<strong>in</strong>d the centre of gravity of an area bounded 2 = t/ 2px and x* = 2py.<br />

by the curves<br />

17f>0**. a) F<strong>in</strong>d the centre of gravity of a semicircle us<strong>in</strong>g<br />

Guld<strong>in</strong>'s theorem.<br />

b) Prove by Guld<strong>in</strong>'s theorem that the centre of gravity of<br />

a triangle is distant from its base by one third of its altitude<br />

Sec. 12. Apply<strong>in</strong>g Def<strong>in</strong>ite Integrals to the Solution of Physical <strong>Problems</strong><br />

1. The path traversed by a po<strong>in</strong>t. If a po<strong>in</strong>t is <strong>in</strong> motion along some<br />

curve and the absolute value of the velocity o~/(/) is a known function of<br />

the time t, then the path traversed by the po<strong>in</strong>t <strong>in</strong> an <strong>in</strong>terval of time<br />

'. * is<br />

Example 1. The velocity of a po<strong>in</strong>t is<br />

o = 0. 1/ 8<br />

m/sec.<br />

F<strong>in</strong>d the path s covered by the <strong>in</strong>g the<br />

po<strong>in</strong>t<br />

commencement ol motion.<br />

<strong>in</strong> the <strong>in</strong>terval<br />

What is the<br />

of time 7=10 sec<br />

mean velocity cf<br />

follow-<br />

motion<br />

this <strong>in</strong>terval?<br />

dur<strong>in</strong>g

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