ADA Physics question 11!

[luvely]

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hey guys i haven't seen a thread on question 11 on the ADA practice test. I'm guessing because it's a very simple problem but I'm just a little uncertain about these type of questions. 😳 if someone could make it more clear please!


11. A small girl applies a horizontal force of 2
Newtons to a 10-Newton box which slides
across the floor with a constant speed of 3
m/s. What is the frictional force, in Newtons,
by the floor on the box?
A. 2
B. 6
C. 8
D. 10
E. 12

Answer is A. 2.
thanks!

 

[Shnurek]

So if the velocity of the object is constant, therefore the force being applied is being counter-acted by the frictional force and they are equal. The actual velocity is irrelevant as long as it is constant.

Lets say the object weighed 30 lbs and was traveling at a constant 10m/s with a horizontal force of 2N being applied, the frictional force would still be 2N in the opposite direction. (Every action has an equal and opposite reaction) -Newton's Third Law

 

[crazypal]

So if the velocity of the object is constant, therefore the force being applied is being counter-acted by the frictional force and they are equal. The actual velocity is irrelevant as long as it is constant.

Lets say the object weighed 30 lbs and was traveling at a constant 10m/s with a horizontal force of 2N being applied, the frictional force would still be 2N in the opposite direction. (Every action has an equal and opposite reaction) -Newton's Third Law

+1 except its more like his second law (the third law would be that the object applies 2N of force on the girl)

 

[luvely]

Got it and got it. Thanks!!