Two students are investigating the relationship between net force and acceleration on an object. they tie a string to a 1-kg block resting on a horizontal table. the string is run over a pulley and attached to a 100-gram weight hanging above the floor. the acceleration of the block is then calculated as the block falls to the floor. which statement would best describe the greatest source of error in this investigation and suggest a reasonable method to reduce this error? a) the block would have friction and a dynamic cart could be used. b) the block on the table has too much mass and should be increased c) the falling mass is too small to accelerate the block and should be increased. d) a pulley has friction and the hanging mass should be replace with a spring scale. r