Bob and Jenny decide to play tug-of-war while wearing roller skates (i.e., assum
ID: 1955971 • Letter: B
Question
Bob and Jenny decide to play tug-of-war while wearing roller skates (i.e., assume frictionless). Jenny is considerably stronger than Bob, but Bob weighs 160 lbs while Jenny weighs 120 lbs. Who loses the match by crossing over the midline first? Explain your answer from two different perspectives, both in terms of acceleration and in terms of linear momentum.
Now in the ultimate rematch, they replace their roller skates with sneakers. Given what we know about friction, why is it practically guaranteed that the first person to start slipping will lose?
Explanation / Answer
in the frictionless scenario, bob will be the winner. when they pull, they will both be pulled towards the center line with respect to acceleration, an equal force jenny will be quicker to accelerate. with respect to linear momentum, jenny will have a higher velocity to maintain the same momentum, so shell cross the line first. with friction, whoever slips first will start to accelerate. the coefficient of kinetic friction is lower than that of static friction, so the acceleration will continue unless traction can be regained