T inapplicable for the entire motion of an object falling through air?","back":"The acceleration is non-uniform (not constant) because the drag force changes with speed.","points":2,"mcqOptions":[{"text":"The acceleration is non-uniform (not constant) because the drag force changes with speed.","correct":true,"explanation":"As the object speeds up, drag increases, changing the resultant force and therefore the acceleration. SUVAT equations require constant acceleration, so they cannot describe the entire fall."},{"text":"The acceleration is uniform (constant) because the object's weight does not change with speed.","correct":false,"explanation":"Constant weight does not imply constant acceleration because the opposing drag force changes as speed changes. The resultant force and acceleration are therefore non-uniform during the fall."},{"text":"The acceleration is zero because the drag force balances the object's weight throughout the fall.","correct":false,"explanation":"Drag balances weight only after terminal velocity is reached, not throughout the fall. Before then, changing drag produces a changing resultant force and non-uniform acceleration."},{"text":"The acceleration is uniformly increasing because the drag force becomes larger as the object speeds up.","correct":false,"explanation":"Increasing drag makes the resultant downward force and acceleration decrease rather than increase uniformly. Because drag varies with speed, acceleration is non-uniform and SUVAT is inapplicable overall."}]},{"id":"2c89ae13-f6b6-4940-88de-03215159f145","cardType":"basic","front":"In what direction does drag act relative to an object's motion?","back":"Opposite to the direction of motion through the fluid.","points":1,"mcqOptions":[{"text":"Opposite to the direction of motion through the fluid.","correct":true,"explanation":"Drag resists relative motion between an object and the surrounding fluid, so its force acts opposite to the object's direction of motion through that fluid."},{"text":"Parallel to the direction of motion through the fluid.","correct":false,"explanation":"A force acting along the motion would accelerate the object rather than resist it. Drag acts opposite to the relative motion through the fluid."},{"text":"Perpendicular to the direction of motion through the fluid.","correct":false,"explanation":"A perpendicular force changes direction rather than directly opposing motion, as with centripetal force. Drag acts opposite to the object's motion relative to the fluid."},{"text":"Upward relative to the direction of motion through the fluid.","correct":false,"explanation":"Drag is upward only when the object's relative motion through the fluid is downward. In general, it acts opposite to the direction of relative motion."}]},{"id":"ac2aee59-ccb9-4bb2-9705-fe8788aa91d8","cardType":"basic","front":"List three physical factors that increase the drag force on an object in air.","back":"

Higher speed
Larger frontal area
Greater air density

","points":3,"mcqOptions":[{"text":"

Higher speed
Larger frontal area
Greater air density

","correct":true,"explanation":"Drag generally increases when the object moves faster, presents a larger frontal area, or travels through denser air, because each increases interaction with the air."},{"text":"

Lower speed
Smaller frontal area
Lower air density

","correct":false,"explanation":"This reverses all three relationships: lower speed, smaller frontal area and lower air density each reduce aerodynamic drag. Their higher or greater counterparts increase it."},{"text":"

Higher speed
Smaller frontal area
Lower air density

Motion with non-uniform acceleration

Motion with non-uniform acceleration Flashcards

Motion with non-uniform acceleration

Motion with non-uniform acceleration Flashcards