Physics

Physics

Problem

A 3.0 kg3.0\,\text{kg} cart moves 6.0 m/s6.0\,\text{m/s} east on a nearly frictionless horizontal track. A laboratory air jet fixed to the room exerts a constant 4.0 N4.0\,\text{N} force westward on the cart for 0.80 s0.80\,\text{s}. Immediately afterward, a 1.0 kg1.0\,\text{kg} brick is dropped straight down into the cart so that it lands without bouncing and moves together with the cart. Neglect all other forces. Which of the following gives the cart–brick system’s speed and direction after both events have occurred? a) 4.5 m/s4.5\,\text{m/s} east b) 3.7 m/s3.7\,\text{m/s} east c) 2.1 m/s2.1\,\text{m/s} east d) 4.9 m/s4.9\,\text{m/s} east

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