# Calculate the work done by the mover

1. Homework Statement
A mover pushes a 85kg crate along the floor at a constant speed through a displacement of 3,1m[E]. The coefficient of kinetic friction between the floor and crate is 0.22.
A) Calculate Fn and Fapp.
B] Calculate the work done by the mover.

3. The Attempt at a Solution
Fg=mg
=85kg*9.8N/kg
Fg=833N
So Fn=Fg
but how can i find Fapp

B] w=183N*3.1m
w=567.3

Last edited:

daniel_i_l
Gold Member
The box is moving at a constant speed, what does that say about the sum of the forces on the box?

plz helpp.............

arildno
Homework Helper
Gold Member
Dearly Missed
What does the word constant mean??

What does the word constant mean??

not changing

daniel_i_l
Gold Member
Yes, so what is the acceleration of the box? How can you use that to find the sum of all the forces?

Yes, so what is the acceleration of the box? How can you use that to find the sum of all the forces?
So a=0
Fnet=0
Fnet=Fapp+Ff
Fapp=0-180
Fapp=180
is that right?

Last edited:
$$Given$$

$$m=0.2kg$$
$$\Delta {h}_{1}=0.835m$$
$${v}_{1}=0m/s$$

$$Required$$

$${E}_{g} and {E}_{k}$$

$$Solution$$

$${E}_{g}={m}g\Delta h$$
$$={0.2kg}*9.8N/kg*0.835m$$
$${E}_{g}=1.63J$$

$${E}_{k}=(1/2)m{v}_{1}^2$$
$$=(1/2)0.2Kg(0m/s)^2$$
$${E}_{k}=0J$$

$${E}_{T}=1.56J$$

Last edited:
no response

arildno
Homework Helper
Gold Member
Dearly Missed
Where did you get the 180 from, and why did you cut out the sign in front of it?

Hootenanny
Staff Emeritus
Gold Member
Your working seems ok, but I don't know where you got 180 from. Check your math...

Edit: Dammit, thats three times thats happened today :grumpy:

Your working seems ok, but I don't know where you got 180 from. Check your math...

Edit: Dammit, thats three times thats happened today :grumpy:

soory i mean 183

arildno
Homework Helper
Gold Member
Dearly Missed
I couldn't care less if the number was 54 or square root of pi fifths.

I want you to tell us:

1. HOW did you arrive at that number??

2. WHY did you take away the sign?