A box with an initial speed of #5 m/s# is moving up a ramp. The ramp has a kinetic friction coefficient of #5/7 # and an incline of #(3 pi )/8 #. How far along the ramp will the box go?

1 Answer
Jun 12, 2017

Answer:

The distance is #=1.07ms^-1#

Explanation:

Taking the direction up and parallel to the plane as positive #↗^+#

The coefficient of kinetic friction is #mu_k=F_r/N#

Then the net force on the object is

#F=-F_r-Wsintheta#

#=-F_r-mgsintheta#

#=-mu_kN-mgsintheta#

#=mmu_kgcostheta-mgsintheta#

According to Newton's Second Law

#F=m*a#

Where #a# is the acceleration

So

#ma=-mu_kgcostheta-mgsintheta#

#a=-g(mu_kcostheta+sintheta)#

The coefficient of kinetic friction is #mu_k=5/7#

The incline of the ramp is #theta=3/8pi#

#a=-9.8*(5/7cos(3/8pi)+sin(3/8pi))#

#=-11.73ms^-2#

The negative sign indicates a deceleration

We apply the equation of motion

#v^2=u^2+2as#

#u=5ms^-1#

#v=0#

#a=-11.73ms^-2#

#s=(v^2-u^2)/(2a)#

#=(0-25)/(-2*11.73)#

#=1.07m#