An Atwood’s machine consists of blocks of masses m1=10.0 kg and m2 = 20.0 kg attached by a cord running over a pulley as in the figure below: The pulley is a solid cylinder with mass M=8.00 kg and radius r=0.200 m. The block of mass m2 is allowed to drop, and the cord turns the pulley without slipping. a) Why must the tension T2 be greater than the tension T1? b) What is the acceleration of the system, assuming the pulley axis is frictionless? 6 c) Find the tensions T1 and T2.

Simon is writing a story about an astronaut whose spacecraft has been boarded by space pirates. the astronaut has her lucky penny in her hand behind her back as the space pirates break into the control room. she has just locked the controls so that the ship is accelerating in the direction of the control room’s ceiling. simon wants the astronaut to use the penny to hit a button on the control panel to turn off the lights and escape. the button is located a short distance behind and below the astronaut’s hands. how should simon use the theory of relativity to describe what the astronaut must do in order to hit the button?