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Homework Statement
The three thin rods shown below are initially at the same angle, with one rod twice as long as each of the others two.
Rod X is made of brass (density = 8.6 g/cm3), the others are made of aluminum (density = 2.7 g/cm3). All rods are released from rest at the same time. Select an answer for each statement below.
A. Time for Z to reach the ground is ... for Y. (greater than, less than, or equal to)
B. The initial linear acceleration of the top end of Y is ... that of Z. (greater than, less than, or equal to)
C. Just before landing the kinetic energy of X is ... that of Y. (greater than, less than, or equal to)
The attempt at a solution
Here is my reasoning. For part A, Z would take longer, since the center of mass of the rod has a greater distance to fall. For part B, the linear accelerations would be the same, since gravity acts the same on both of them. For part C, the kinetic energy of X would be greater than Y since X will have a greater mass and K=(1/2)mv^2. One or more of my answers are wrong, though, so can anyone see where I'm going astray?
Thank you for your help.
The three thin rods shown below are initially at the same angle, with one rod twice as long as each of the others two.
Rod X is made of brass (density = 8.6 g/cm3), the others are made of aluminum (density = 2.7 g/cm3). All rods are released from rest at the same time. Select an answer for each statement below.
A. Time for Z to reach the ground is ... for Y. (greater than, less than, or equal to)
B. The initial linear acceleration of the top end of Y is ... that of Z. (greater than, less than, or equal to)
C. Just before landing the kinetic energy of X is ... that of Y. (greater than, less than, or equal to)
The attempt at a solution
Here is my reasoning. For part A, Z would take longer, since the center of mass of the rod has a greater distance to fall. For part B, the linear accelerations would be the same, since gravity acts the same on both of them. For part C, the kinetic energy of X would be greater than Y since X will have a greater mass and K=(1/2)mv^2. One or more of my answers are wrong, though, so can anyone see where I'm going astray?
Thank you for your help.