Explanation:
The net force along the horizontal direction is

where f is the frictional force. We can find the frictional force by looking at the vertical forces acting on the couch:

From the definition of frictional force,


Therefore, the net force on the couch is

Answer:
Explanation:
Given that,
Initial Angular velocity w=500rpm
Converting from rpm to rad/s
1rev =2πrad
1minutes =60secs
500rpm=500rev/mins
w = 500×2π/60
wi=52.36rad/s
The final angular velocity wf=0rad/s
Time to stop is t=2.6sec
We want to find angular acceleration α
Using the equation of angular motion
wf = wi + αt.
0 = 52.36 + 2.6α
-52.36=2.6α
α = -52.36/2.6
α = -20.14rad/s²
The angular acceleration is negative because it is decelerating.
Then, α=20.14rad/s²
<span>The correct answer is option C. i.e.Equilateral triangles. All equilateral triangle have equal sides. Due to this these set of shapes will always be similar. Similarity in the sense that only the size of the triangles can change to large or smaller but the shape will be be similar always.</span>