A student pushes a 40-N block across the floor for a distance of 10 m. How much work was applied to move the block?

A.
4 J

B.
40 J

C.
400 J

D.
4000 J

Question

A student pushes a 40-N block across the floor for a distance of 10 m. How much work was applied to move the block? 	
	
 
A.
	4 J
	
 
B.
	40 J
	
 
C.
	400 J
	
 
D.
	4000 J

testing123guest · Answer

@hartnn this is a study guide and i have a test in a week i am studying for plz help with this one i am stuck on

hartnn · Answer

Work = Force * Displacement 

use that^

trojanpoem · Answer

|dw:1452100933268:dw|

trojanpoem · Answer

@hartnn , he can't he wasn't given the force but the weight.

hartnn · Answer

40N seems to be a force and not weight, right?

weight would be 40kg

trojanpoem · Answer

@hartnn , Weight = mg ( mass * gravity)  unit : Newtons

trojanpoem · Answer

Kg is for mass

hartnn · Answer

Unit of Force is Newton.

trojanpoem · Answer

Weight is a force

hartnn · Answer

okay :)
I'll let you continue on this :)

trojanpoem · Answer

@hartnn , I can't solve it without friction coefficient

N = 40 newtons

F_push = Friction = mu * N

Work = F_push * 10

hartnn · Answer

so assume $\mu = 1$

testing123guest · Answer

sorry guys my server was knocked out but i am back have u cam up with something yet

trojanpoem · Answer

@Michele_Laino

trojanpoem · Answer

The question would 've been right if the box with pushed vertically not on a floor.

hartnn · Answer

If I were to choose one,
I would go with 
$40N\times 10m = 400 J$

your teacher might not have thought too much before asking a question on the formula $W = F\times d $

trojanpoem · Answer

@hartnn , I agree.

testing123guest · Answer

awesome thank u i am going to give the medal to trojanpoem because hartnn has alot

hartnn · Answer

wise choice.
Honestly I don't care about medals anymore :P

trojanpoem · Answer

Neither do I. By the way, give you a medal xD

trojanpoem · Answer

I still believe that this question is wrong.

testing123guest · Answer

how long have u been on open study i mean u have answer 12227 question

testing123guest · Answer

@hartnn

hartnn · Answer

not much...just like 3 years...

testing123guest · Answer

holly.. dang man that alot how old are u

testing123guest · Answer

@TrojanPoem  what do u mean u still thing it is wrong

trojanpoem · Answer

The question isn't correct. 

The box is being pushed so the work is the amount of force exerted * displacement, in our case the force given is the weight which is the effect of gravity on mass.

we want the force ( the student exerted) so |dw:1452102280961:dw|

in this drawing we can find that the force = friction coefficient * normal force

normal force = weight.

If the box was to be moved vertically we would have used the weight as a force.
see this:
|dw:1452102333917:dw|

as upward force = weight.

in your case unless you get the friction coefficient you're just putting wrong answer to satisfy your prof.