Question

A wooden rod of negligible mass and length 79.0 cm is pivoted about a horizontal axis through its center. A white rat with mass 0.510 kg clings to one end of the stick, and a mouse with mass 0.210 kg clings to the other end. The system is released from rest with the rod horizontal.

Answer 1

`v=1.307m/s`

Step-by-step explanation:

The velocity of both animals are the same the analysis of the motion is:

`E_(pr)-E_(pw)=K_(Ew)+K_(Er)`

`E_(pw)=m*g*h`,
`h=0.395 cm`

`E_(pw)=0.510kg*9.8m/s^2*0.395m=197.421x10^(-3)J`

`E_(pr)=m*g*h`,
`h=0.395 cm`

`E_(pr)=0.210kg*9.8m/s^2*0.395m=812.91x10^(-3)J`

Replacing in the initial equation now solve to velocity in this case is the same for both animals so:

`615.489x10^(-3)J=(1)/(2)*v^2[0.51+0.21]kg`

`v^2=(1.2309J)/(0.72kg)=1.709m^2/s^2`

`v=1.307m/s`