Question

part e
set the friction slider to
one\ and the ice will appear again. give the crate a quick push. note that the sum of forces drops down to zero. however, the crate keeps moving. why?
self - evaluation
how did you do? rate your work on a scale of 1 to 5, with 5 as the highest score. then write a brief evaluation of your work below. note what you learned and what challenged you.

Explanation:

According to Newton's first law of motion, an object in motion will stay in motion with a constant velocity unless acted upon by an external force. When the friction slider is set to "none", there is no frictional force to oppose the motion of the crate. So once the crate is given a push and set in motion, with the sum of forces being zero (no friction and no other horizontal forces acting), it continues to move due to its inertia.

Answer:

The crate keeps moving because according to Newton's first law, in the absence of an external force (such as friction in this case), an object in motion will maintain its state of motion due to inertia.