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A small block with a mass of 0.150kg is attached to a cord passing through a hol

ID: 1281411 • Letter: A

Question

A small block with a mass of 0.150kg is attached to a cord passing through a hole in a frictionless, horizontal surface (Figure 1) . The block is originally revolving at a distance of 0.50m from the hole with a speed of 0.20m/s . The cord is then pulled from below, shortening the radius of the circle in which the block revolves to 0.15m . At this new distance, the speed of the block is observed to be 0.67m/s .

Part A

What is the tension in the cord in the original situation when the block has speed v0 = 0.20m/s ?

Part B

What is the tension in the cord in the final situation when the block has speed v1 = 0.67m/s ?

Part C


n

A small block with a mass of 0.150kg is attached to a cord passing through a hole in a frictionless, horizontal surface (Figure 1) . The block is originally revolving at a distance of 0.50m from the hole with a speed of 0.20m/s . The cord is then pulled from below, shortening the radius of the circle in which the block revolves to 0.15m . At this new distance, the speed of the block is observed to be 0.67m/s . Part A What is the tension in the cord in the original situation when the block has speed v0 = 0.20m/s ? Part B What is the tension in the cord in the final situation when the block has speed v1 = 0.67m/s ? Part C How much work was done by the person who pulled on the cord?

Explanation / Answer

a) T = m*v*v/r = 0.012 N

b)T = 0.4489 N

c)

W = 0.5*0.15*(0.67*0.67 - 0.2*0.2 ) = 0.0306 J