1answers
i)3.2 to the right
ii)2 to the right
A slab of mass M = 15 kg can move without friction over a level floor. A mass m = 10 kg is placed on the slab, and a massless string passed over two pulleys fastened to the slab is attached to it. The coefficient of friction between the mass m and the slab is μ = 0.6. What acceleration will the slab move with if a constant force of F = 80 N is applied to the free end of the string? Consider two cases: (i) the force is directed horizontally, (ii) the force is directed vertically upward.
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6 Answers
1for the first one
net force on M due tension =0 as they cansel out
let frction on m be f backwards
first we will consider friction is static and see i.e. both have the same acceleration
we get
F-f/m=f/M
80-f/10=f/15
80-f/2=f/3
f=240/5=48
hence acceleration=
F-f/m=80-48/10=3.2
in the second case observe a froce F is acting on pully net bacwarkds due to tension
let friction act backwards on m
then
attempting to keep ststic friction
f-F/M=F-f/M
thus F=f=80 but maximum f=μN=60
so here maximum friction i.e. 60 will act
thus acceleration = 80-60/10=2
66sorry you probably worked out the acceleration of m (I thought it was for M). The slab is the bigger mass.