Group Problem #18 Physics 11-4 S12 Page 2 of 4

Group Problem #18 Physics 11-4 S12 Page 1 of 4

Group problem #18: torque

For the vector quantities and , find both and . What is the relationship between your two answers?

If and and , what is ? What is the angle between and ? Group Problem #18 Physics 11-4 S12 Page 2 of 4

The automatic flag raising system on a horizontal flagpole attached to the vertical outside wall of a tall building has become stuck. The management of the building wants to send a person crawling out along the flagpole to fix the problem. Because of your physics knowledge, you have been asked to consult with a group to decide whether or not this is possible. You are all too aware that no one could survive the Group Problem #18 Physics 11-4 S12 Page 3 of 4

250 foot fall from the flagpole to the ground. The flagpole is a 120lb steel L-beam which is very strong and rigid. One side of the flagpole is attached to the wall of the building by a hinge so that it can rotate vertically. Nine feet away, the other end of the flagpole is attached to a strong, lightweight cable. The cable goes up from the flagpole at an angle of 30° until it reaches the building where it is bolted to the wall. The mechanic who will climb out on the flagpole weighs 150lbs including equipment. From the specifications of the building construction, both the bolt attaching the cable to the building and the hinge have been tested to hold a force of 500 lbs. Your boss has decided that the worse case is when the mechanic is at the far end of the flagpole, nine feet from the building.

You have a summer job working downtown washing windows on skyscrapers (the pay is great and so are the medical benefits). The platform you and your partner are using to get to the windows is a meter wide and four meters long. You know from hauling the platform out of your truck countless times that it Group Problem #18 Physics 11-4 S12 Page 4 of 4 has a mass of 70 kg. It is supported by two cables, one at each end, mounted on-center to prevent the platform from tipping over as it is pulled up the side of the building at a constant speed. If you (mass of 55 kg) are standing on the platform 1 meter from one cable while your partner (mass of 87 kg) is 1.3 meters from the other cable and both of you are half a meter from the side, what is the tension in each cable? Assume the platform has a uniform mass distribution and is of negligible thickness.