WorkA boys drags a wooden crate with a distance of 12m, across a rough level floor at a constant speed of 1.5 m/s by pulling on the rope tied to...

The figure is
below.

a)

The force applied
can be decomposed into its horizontal and vertical
components.

`F_h = F*cos(alpha) =50*cos(25) =45.32 N`

`F_v = F*sin(alpha) = 50*sin(25) =21.13 N`

b)

The speed of the box is
constant, it means there is no acceleration. The sum of forces on the horizontal and
vertical axis need to be zero.

On the horizontal:
horizontal component of force need to equal the friction force `F_h = Ff =45.32 N`

On the vertical: the difference between the box weight and
the vertical force is equal to the reaction from the ground`G-Fv =N`

Since the mass of the box is not give one can not
determine the magnitude of these forces on the vertical
axis.

c) On the horizontal axis the work done by the
horizontal force (positive) is equal in absolute value with the work done by the
friction force (negative)

`W = F_h*d =45.32*12 =543.84 J`

On the vertical axis because there is no displacement the
work done by each of the three forces is zero.

d) As stated
above, the total amount of work done by all forces on the object is
zero.

e) Since the mass of the object is not given, the
coefficient of friction can not be determined.

Images:
class="imageTiles" colwidth="220">

uploadid="981">

class="image">
Image (1 of 1)

href="/jax/index.php/images?eventHandler=Answer&uploadID=981&answerID=641451"
class="greybox" id="image-float" gb_title="Image" gb_width="1000" gb_height="650"
title="Click to Enlarge">
itemprop="image"
src="http://user-content./ecd292b71af4b548796618242b2db1ad2f2d55f3_thumb.jpg"/>