Select all that apply.
no work is accomplished in which of the following situations?

a boy carried a 4.0-newton box 3.0 meters across the room at a constant velocity.
a boy pushes on a box weighing 4.0 newtons and it doesn't move.
a boy lifts a 4.0-newton box to a height of 1.0 meter.

a boy pushes on a box weighing 4.0 newtons and it doesn't move.

Explanation:

The definition of work is the following:

where

F is the force applied

d is the displacement

is the angle between the direction of the force and of the displacement

From the formula, we notice that if there is no displacement (d=0), then the work done is zero (W=0).

The choices given are:

a boy carried a 4.0-newton box 3.0 meters across the room at a constant velocity.  --> in this case, work is done (displacement is non-zero)

a boy pushes on a box weighing 4.0 newtons and it doesn't move.  --> in this case, NO work is done (because the displacement is zero)

a boy lifts a 4.0-newton box to a height of 1.0 meter. --> in this case, work is done (displacement is non-zero)

So, the correct choice is

a boy pushes on a box weighing 4.0 newtons and it doesn't move.

the working equation for the angular size is the product of the physical size and 360 degrees divided by the product of two pi and distance from earth. the minimum size would be 0.559 degrees while the maximum size would be 0.49 degrees. 

0.11 m/s and 0.28 m/s should be correct