2. (15 points) A dust speck (m = 1 ng) travels horizon- tally at speed u until it hits an ice cube of mass M = 1g
that is sitting at rest on a horizontal frictionless surface.
Having absorbed the dust speck, the ice cube proceeds
to travel horizontally with speed v = 3 ms-1.
What was the initial speed, u, of the dust speck?

Hints: (1) 1 ng = 10-9g. (2) See if you can figure out
why Newton would have gotten this question wrong.
What is the relativistic momentum? Do you need it for
the ice cube? How about the speck of dust?
U

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.

c) up is the direction the magnetic force is acting on the charge.

molecules are free to separate from each other and will take on the shape of the container. molecules move completely at random and high speeds. they vibrate in a fixed position and do not move around much. molecules expand to the edge of their container.