Question

An object sits at the edge of a table top with a mass of 180 kg. It is connected by a magical physics thread to a mass of 250 kg via a pulley which is hanging in the air below the edge of the table top. There is an unknown amount of friction between the 180 kg mass and the table. The entire thing is accelerating at 2 m/s/s towards the edge of the table (250 kg mass is moving down).
What is the force of friction?
What is the coefficient of friction?

Answer 1

Answer:

Force of Friction = 1640 N

Coefficient of friction = 0.911

Explanation:

forces act on the objects as shown in the graph.

Fx=Foroce of friction

T=tension of the thread

R=Normal Force(R=1800N)

μ= friction coefficient

a=acceleration = $2ms^{-2}$

applying F=ma to 250kg object downwards

$F=m*a\\2500-T=250*2\\T=2000N$

applying F=ma to 180kg object rightwards

$F=m*a\\\\T-F_x=m*a\\2000-F_x=180*2\\F_x=1640N$

According to Frictional Force Formula,

$F_x=$μ*R

1640=μ*1800

μ=0.911