A box with an initial speed of #5 m/s# is moving up a ramp. The ramp has a kinetic friction coefficient of #7/2 # and an incline of #(5 pi )/12 #. How far along the ramp will the box go?

1 Answer
May 14, 2017

Answer:

The distance is #=0.68m#

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)#

#a=-9.8*(7/2cos(5/12pi)+sin(5/12pi))#

#=-18.34ms^-2#

The negative sign indicates a deceleration

We apply the equation of motion

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

#u=5ms^-1#

#v=0#

#a=-18.34ms^-2#

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

#=(0-25)/(-2*18.34)#

#=0.68m#