# physics question-kinetic friction

• September 21st 2010, 01:20 PM
Jessica11
physics question-kinetic friction
A 26 kg box is being pushed across the floor by a constant force <103,0,0> N. The coefficient of kinetic friction for the floor and box is .18. At t=6 s the box is at location <10,4,-4>m, traveling with velocity <7,0,0>m/s. What is its position and velocity at t-7.6s?

I don't know where to start help please?
• September 22nd 2010, 12:50 AM
Haytham
you write the equation of motion
the movement is 1-dimensional so you only need 1 equation

$x=x_0 + v_{x0} (t-t_0) + \frac{1}{2} a (t-t_0)²$

you got $x_0$, $v_{x0}$ and $t_0$ in the text
you find $a$ with Newton's 2nd law