A small block with mass m1 rest on a frictionless horizontal tabletop a distance
ID: 1906175 • Letter: A
Question
A small block with mass m1 rest on a frictionless horizontal tabletop a distance r1 from a hole in the center of the table. A light, stretchless string tied to the small block passes down through the hole, and a larger block with mass m2 is suspended from the free end of the string. The small block, which can be considered a particle, is set into uniform circular motion with radius r and speed v. A) Find the value of v for the small block such that the large block will not move. B) If you then pull down the large block so that the small block is rotating at a distance r2, what is its new velocity? C) How much net work was done pulling down the large mass?Explanation / Answer
A)centripetal force=m1v^2/r therefore m1v^2/r=m2g v=sqrt(m2gr/m1) b)v=sqrt(m2gr2/m1) c)net workdone=(r-r2)*net force net force=m2g