Physics
Physics
Problem
Four identical carts on identical horizontal tracks experience the horizontal force(s) indicated below. Assume friction is negligible. A. Cart moves east; forces: east and west. B. Cart moves west; forces: west and east. C. Cart moves north; single south force. D. Cart moves east; single east force. For which cart is the direction of the cart’s acceleration opposite to the direction of its instantaneous velocity? a) Cart A b) Cart C c) Cart B d) Cart DIntuitive explanation
The key insight is that acceleration depends on net force, not on which way the cart is currently moving. A cart accelerates opposite to its velocity when the net force points backward—that is, when the forces resist or reverse the cart's motion. Check each scenario by finding the net force direction, then compare it to the velocity direction.
Intuitive explanation
The key insight is that acceleration depends on net force, not on which way the cart is currently moving. A cart accelerates opposite to its velocity when the net force points backward—that is, when the forces resist or reverse the cart's motion. Check each scenario by finding the net force direction, then compare it to the velocity direction.