PHYS 3210 Midterm: PHYS 321 UVA MidtermSolutions 02
Document Summary
Phys 321 midterm exam (21 october 2002) solutions: 1 of 3. Time: 1 hour: a spool of thread rests on a horizontal table, as shown. The end of the thread is pulled upward at an angle to the horizontal. The thread passes under the core of the spool, and is pulled with tension t . There is a leftward-pointing tangential force xt and table. , but the table exerts an upward normal force. T at the point of contact between spool cos sin zt. Fr tr and the law for rotational motion about the axis of the spool reads. Finally, as long as the spool rolls without slipping, x convention that counter-clockwise rotations are positive. ) We can use newton"s 2nd law in the x-direction to eliminate the unknown force f. Finally, we use x to get an equation for & : 0 so that the spool does not accelerate upward (it remains in contact (the sign comes from the.
