Window Washer Problem (Forces)

[zm87]

A window washer pulls herself upward using a bucket-pulley apparatus. How hard must she pull downward to raise herself slowly at constant speed? If she increases this force by 10% what will her acceleration be? The mass of the person and bucket is 65 kg.

Need some help, gracias.

 

[HallsofIvy]

Force= mass * accleration.

If the person is moving at constant speed (no acceleration) that means there is no net force- she is pulling just enough to equal her weight. You are given that her mass is 65 kg. What is her weight?

Now, increase that pull by 10%. Subtract off her weight again to get net force and use "force equals mass times acceleration".

 

[M98Ranger]

In order to raise herself slowly at a constant speed, the window washer must exert a downward force equal to her weight. This weight can be calculated using the formula W = mg, where m is the mass and g is the acceleration due to gravity (9.8 m/s^2). Therefore, the window washer must pull downward with a force of approximately 637 N (65 kg x 9.8 m/s^2) to raise herself slowly at a constant speed.

If she were to increase this force by 10%, her new downward force would be approximately 701 N (637 N x 1.1). This change in force would result in an acceleration of 0.15 m/s^2 (701 N / 65 kg). This means that her speed would increase by 0.15 meters per second every second.

It is important for the window washer to carefully consider the force she exerts in order to maintain a constant speed and ensure her safety. Any significant changes in force could result in a sudden acceleration or deceleration, which could be dangerous while working at heights. Proper training and understanding of the forces involved in the bucket-pulley apparatus is crucial for the safety of the window washer.