Hey guys, I have a conceptual physics problem my teacher has assigned to aid me
ID: 2068150 • Letter: H
Question
Hey guys, I have a conceptual physics problem my teacher has assigned to aid me in preparation for an upcoming exam. If you could assist me in solving this problem, I would be very appreciative. Thank you =)Bernice pushes a heavy crate across the horizontal floor of her lab. There is friction between the crate and the floor. During a particular interval, the crate moves a distance x toward the back of the lab, moving at a constant velocity the entire time.For each question below, choose an answer and explain why it is correct. (This is a purely conceptual problem; you do not need to calculate anything, though you may wish to refer to certain equations in your explanations.)
A)Is the work done by Bernice on the crate positive , negative, or zero?
B)Is the work done by the frictional force on the crate positive, negative, or zero?
C) Is the work done by gravity on the crate positive, negative, or zero?
D) Is the total work on the crate positive, negative, or zero?
Explanation / Answer
A) Since Bernice is applying a force in the direction of motion, she does positive work. B) Since the frictional force acts against the motion, it does negative work. C) Since gravity is perpendicular to the motion, it does no work. D) Since the total energy of the block remains the same (as neither kinetic nor potential energy changes), the total work is zero.