A21 kg chair initially at rest on a horizontal floor requires a 175 n horizontal force to set it in motion. once the chair is in motion, a 137 n horizontal force keeps it moving at a constant velocity. the acceleration of gravity is 9.81 m/s 2 . a) what is the coefficient of static friction between the chair and the floor?

Explanation:

Given

mass of chair m=21 kg

Force required to set chair in motion is 175 N

Once the chair is in motion 137 N is require to move it with constant velocity

i.e. 175 N is the amount of force needed to just overcome static friction and 137 is the kinetic friction force

thus

where is the coefficient of static friction and N is Normal reaction

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

read more on -

this means that the temperature of both substances will be equal