Calculate the work done by the mover

[raman911]

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

 

[daniel_i_l]

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

 

[raman911]

please helpp....

 

[arildno]

What does the word constant mean??

 

[raman911]

What does the word constant mean??

not changing

 

[daniel_i_l]

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

 

[raman911]

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?

 

[raman911]

$$Given$$

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

$$Required$$

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

$$Solution$$

$${E}_{g}={m}g\Delta h$$
$$={0.2kg}*9.8N/kg*0.835m$$
$${E}_{g}=1.63J$$$${E}_{k}=(1/2)m{v}_{1}^2$$
$$=(1/2)0.2Kg(0m/s)^2$$
$${E}_{k}=0J$$

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

 

[raman911]

no response

 

[arildno]

Where did you get the 180 from, and why did you cut out the sign in front of it?

 

[Hootenanny]

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

Edit: Dammit, that's three times that's happened today

 

[raman911]

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

Edit: Dammit, that's three times that's happened today

soory i mean 183

 

[arildno]

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?