A student of total mass stands on a frictionless skateboard
PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Force and Translational Dynamics · Force and Translational Dynamics
Problem
A student of total mass 60kg stands on a frictionless skateboard. She pulls horizontally on a light rope that is tied to a fixed post embedded in the ground. The rope tension is measured to be 50N.
(1) If the system is defined as the student plus skateboard only, classify the tension force as internal or external to the system and justify your answer.
(2) Using your classification from part (a), determine the magnitude of the acceleration of the student–skateboard system.
(3) The system is now redefined to include the Earth in addition to the student and skateboard. Reclassify all forces acting on this larger system as internal or external and state the resulting acceleration of this expanded system’s center of mass. Provide a brief explanation.