# Help Stuck on these 2 problems

Help!!! Stuck on these 2 problems

1. Determine the motions equations of an ideal pendulum of mass m and lengh r.

2. A machine is formed by a homogenous cylinder of radio R and mass M. It rotates in its axel (frictionless). A mass by an inextensible cord (massless) is roller to cylinder. Find the motions equations.

Andrew Mason
Homework Helper
joselyn said:
1. Determine the motions equations of an ideal pendulum of mass m and lengh r.
This is fully explained in many texts. All you need to work out is the tangential restoring force on the pendulum mass:

$$F_{tang} = ma_{tang}$$ = tangential component of mg.

2. A machine is formed by a homogenous cylinder of radio R and mass M. It rotates in its axel (frictionless). A mass by an inextensible cord (massless) is roller to cylinder. Find the motions equations.
I am not sure I understand the problem here. Is the mass on a horizontal frictionless surface begin rolled toward the cylinder or is it rotating about the cylinder?

AM