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.
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:
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 by-manufactured 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.