A 200 W vacuum cleaner is powered by an electric motor whose efficiency is 70%. (Note that the electric motor delivers 200 W of
1 answer:
Answer:
The rate at which this vacuum cleaner supply energy to the room when running is 285.71 Watts.
Explanation:
power efficiency of electric motor = 70% = 0.70
The power output of the vacuum cleaner == 200 W
The power output of the vacuum cleaner =
The rate at which this vacuum cleaner supply energy to the room when running is 285.71 Watts.
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Answer:
<em>866.1 N</em>
Explanation:
The torque on the flywheel = 300 N-m
The force from the hydraulic cylinder will generate a moment on CA about point A.
The part of this moment that will be at point B about A must be proportional to the torque on the cylinder which is 300 N-m
we know that moment = F x d
where F is the force, and
d is the perpendicular distance from the turning point = 1 m
Equating, we have
300 = F x 1
F = 300 N this is the frictional force that stops the flywheel
From F = μN
where F is the frictional force
μ is the coefficient of static friction = 0.4
N is the normal force from the hydraulic cylinder
substituting, we have
300 = 0.4 x N
N = 300/0.4 = 750 N
This normal force calculated is perpendicular to CA. This actual force, is at 30° from the horizontal. To get the force from the hydraulic cylinder R, we use the relationship
N = R sin (90 - 30)
750 = R sin 60°
750 = 0.866R
R = 750/0.866 = <em>866.1 N</em>
