A window washer pushes his scrub brush up a vertical window at constant speed by applying a force as shown in the figure below. The brush weighs 12.3 N, θ = 55.2° and the coefficient of kinetic friction is μk = 0.143.
magnatude of force??
normal force by window to brush.
3 Answers

If 55.2 degrees is the angle between horizontal and the handle, then resolve the force applied to the handle into horizontal and vertical components:
Fx=Fcos55.2
Fy=Fsin55.2
Fnormal = Fcos55.2 (since it is not accelerating in the x direction)
Fup – Ffric – wt = (mass)*(acceleration in the y direction)
Fsin55.2 – 0.143(Fcos55.2) – 12.3N = 0
Solve this equation for F. Then you can plug into Fcos55.2 to get the magnitude of the normal force.

Acceleration is a vector, defined by using fact the bymanufactured from speed (no longer speed) with know to time. by using fact that speed is a vector with a speed and course, however if the cost is continuing if the course is changing there is an acceleration happening. A actual occasion of it is centripetal stress. power a motor vehicle at a continuing speed in a circle. you will sense the stress pushing you outwards radially. by using fact which you sense a stress performing and F=mA you recognize there is an acceleration happening however if the speedometer remains fixed.

Hi