In the figure, a slab of mass m1 = 21 kg rests on a frictionless floor, and a block of mass m2 = 9 kg rests on top of the slab. Between block and slab, the coefficient of static friction is 0.30, and the coefficient of kinetic friction is 0.20. The block is pulled by a horizontal force of magnitude 58 N. What is the acceleration of the slab?
2007-10-02 09:26:34 · 1 answers · asked by Anonymous in Science & Mathematics ➔ Physics
First lets see if the block will slide on the slab
The static friction is
f=u m g = .3 x 9 x 9.81= 26.5 N (so it will definitely slide if pulled by a 58 N force)
The force of kinetic friction is then
fk= .2 x 9 x 9.81=17.7N
This is the force that is being exerted on the slab by moving the block of mass m2.
F=ma and in our case
F=m1a
a=F/m1= 17.7/21=0.84 m/s^2
2007-10-06 03:22:01 · answer #1 · answered by Edward 7 · 0⤊ 0⤋