when isabella pushes a box of mass 5.25 kilograms with a force of 15.7 newtons, it accelerates by a rate of 2.50 meters/second. what is the force due to friction in this scenario?

Question

anonymous · Answer

let force of friction is f so
15.7-f=5.25*2.50

anonymous · Answer

also unit of acceleration is m/s^2

theeric · Answer

Hello, @dirtslinger28 , do you have any more questions on this one?

You see,

$F_{net}=ma$
But you don't know $F_{net}$.

And
$F_{net}=F_{push}+F_{friction}$

So what you're looking at now is that you know everything except for $F_{net}$ and $F_{friction}$.


You can solve this problem by substituting for $F_{net}$. Then $F_{friction}$ is the only unknown variable.
$F_{net}=F_{push}+F_{friction}=ma$
We look at the right two expressions, now.
$F_{push}+F_{friction}=ma$

That's where gyanu left you. Now you can solve for $F_{friction}$, plug in your numbers, and calculate.

anonymous · Answer

F = ma
Force is in Newtons and you have a known 15.7N pushing the box

15.7N = 5.25 kg * acceleration
a = 15.7 / 5.25 = 2.99 m/s^2

So the acceleration with no friction would be 2.99 m/s^2

Since your box goes 2.5 m/s^2, that means the friction force is causing the box to slow by 2.99 m/s^2 - 2.5 = 0.49 m/s^2

Friction is a force and not an acceleration so you have to convert that to Newtons for the friction force:

F = ma 
F = 5.25kg * 0.49 m/s^2
F = 2.6 Newtons , is lost to friction

theeric · Answer

biire2u makes use of the interesting concept of acceleration being additive :)