Question

A 2 kg crate is launched with the same initial velocity of 2 m/s up a rough incline of 45° with a kinetic coefficient of friction of 0.2.

A debate ensues between three great physicists; Emmy Noether, Shing-Tung Yau, and Juan Maldacena. Ms. Noether predicts that the crate will take a longer amount of time to slide up the incline than to slide down because gravity acts in a direction against the crate’s motion as it rises and in the direction of the crate’s motion as it falls. Mr. Yau predicts the crate will take an equal amount of time to rise up the incline and to fall down the incline because when projectiles are thrown upwards they take an equal amount of time to rise and fall. Mr. Maldacena predicts that the crate will take a longer amount of time to slide down the incline than to slide up the incline because kinetic friction slows objects down more and more as time progresses.

Who is right?

Please provide easy to understand explanations of why each physicist is correct or incorrect with step by step mathematical approach.

Answer 1