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1. Start Animation

A 0.25 kg puck (shown in the animation with time in seconds and position in meters) slides on ice at constant speed for two seconds where it then encounters a rough surface. What is the work done by friction in stopping the puck?

2. Start Animation

A string is tied from a smooth peg to a 0.5 kg puck, and the puck is given an initial tangential velocity such that it travels at constant speed in a circle around the peg, as shown in the animation with time in seconds and position in meters. After one second it suddenly encounters a resistive force which eventually stops the puck. What is the magnitude of the work done by the resistive force during the time that it takes to stop the puck?