A house painter uses the character’s chair and pulley to get up from the side of a house. The mass of the painter is 70 kg and the mass of the chair is 10 kg. With what force must he pull the rope down to accelerate upwards at 0.20 m/s^2.
Well, I also hate pulley issues, so take that as a help, not a solution.
Combine the masses to get 80 kg. Weight = Mass multiplied by gravity, so Weight = (80 kg) (-9.81 m/s^2)
Weight = -784.8 Newtons.
I drew a pulley above a box with an arrow going down to 784.8 N with a rope attached to the box (chair) going over the pulley and back to the side of the box.
Add the forces on the Y and remember it’s in motion, so it’s not equal to 0, it’s equal to mass times acceleration.
-784.8 N + 2T (tension of the rope, 2 because you hold it on the other side in tension too)
-784.8N + 2T = (80kg) (0.20m/s^2)
-784.8N + 2T = 16N
2T=800.8N
T = 400.4 N So you need to go down to 400.4 N, or about 90 pounds of downward force. Since the total weight is 800.8 N or 17 = 180 lbs, it seems fair that the pulley weighs half the weight needed to pull. Remember that pulleys make it easier to lift heavy objects. That’s why, when picking up car engines, they’re tied to a multi-pulley pulley system that continues to significantly reduce weight.
Friction and pulley size in this issue have been undone to fix the issue.
Let me know if it’s true
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Pulley Uses
the acceleration of the device is fixed at 0, it exerts an upward deformation stiffness despite the undeniable fact that it is not enough to overcome its weight. 283N is the upward stiffness while the load is 558N, the downward stiffness is greater than the upward stiffness, so it does not change.