# torque problems

1. 1. An 850-N painter stands 1.20 M from one end of a 3.00M scaffold supported at each end by a step ladder. The scaffold weighs 250-N and there is a 40.N can of paint 0.50M from the end opposite the painter. How much force is exerted by each stepladder?

F ladder1 = 642N ladder2= 498N

f

2. 2. Tracy
is building a mobile to hang over her baby’s crib. She hangs a 0.020-kg toy
sailboat 0.010 m from the left end and a 0.015 kg toy truck 0.20 m from the
right end of a bar 0.50 m long. If the arm itself has a negligible mass, where
must the support string be placed so that the arm balances? .135m from left

3. 3. Orin
and Ann, two paramedics, rush a 60.0 kg man from the scene of an accident to a
waiting ambulance, carrying him on a uniform 3.00 kg stretcher held by the
ends. The stretcher is 2.60 m long and the man’s center of mass is 1.00 m from
Ann. How much force must Orin and Ann each exert? Orin = 241N Ann = 376N

4. 4. Nancy,
who’s mass is 60.0 kg is working at a construction site and she sits down for a
bite to eat at noon. If Nancy sits on the very end of a 3.00 m long plank
pivoted in the middle by a saw horse, how much torque must her co-worker
provide on the other end of the plank in order to keep Nancy from falling on
the ground? 882N*m

5. 5. Cilia
is working out in the gym with a 2.00 kg mass that she holds in one hand and
gradually lifts up and down. a) Will Cilia find it easier to lift the mass if
she pivots her arm at the shoulder or at the elbow? B) If Cilia’s arm is 0.60 m
long from her shoulder to her palm and 0.28 m long from her elbow to her palm,
what is the torque of each? a) elbow b) elbow=5.5n*m, shoulder = 11.8N*m

6. 6. A 30.0 N pole is 2.00 m long and has its center of gravity 0.350 m from the heavy end. A fisherman holds the end of the pole in his left hand as he lifts a 100.0 N fish. If his right hand is 0.800 m from the heavy end, how much force does he have to exert to maintain equilibrium? 263N on hand at .8m

7. 7. Mabel
and Maude are seesawing on the school playground and decide to see if the can
move to the correct location to make the seesaw balance. Mabel weighs 400 N and
she sits 2.00 m from the fulcrum of the seesaw. Where should 450 N Maude sit to
balance the seesaw? 1.78m

8. 8. Barry
carries his tray of food to his favorite cafeteria table for lunch. The 0.50 m
long tray has a mass of 0.20 kg and holds a 0.40 kg plate of food 0.20 m from
the right edge. Barry holds the tray by the left edge with one hand, using his
thumb at the fulcrum, and pushes up 0.10 m from the fulcrum with his finger
tips. How much upward force must his finger tips exert to keep the tray level?
B) How might Barry make the tray easier to carry if he still chooses to use
only one hand? a) 16.7m b) hold closer to middle

9. 9. A
uniform bridge, 20.0 m long and weighing 400000 N, is supported by to pillars
located 3.00 m from each end. If a 19600 N car is parked 8.00 m from one end of
the bridge much force does each pillar exert? 207000N 212600N