A meter stick made from a uniform-density material rests on a fulcrum positioned
ID: 1602667 • Letter: A
Question
A meter stick made from a uniform-density material rests on a fulcrum positioned precisely at its middle. If a box of mass m = 3 kg Is suspended from the right end of the meter stick, the system would not be in equilibrium. Where and how could a force be applied to keep the system in equilibrium? (For ease of calculation, consider g = 10 N/kg.) A 30-N downward force at 40-cmmark A 15-N upward force at the 20-cm mark. A 50-N downward force at the 3-cm mark A 75-N upward force at the 70-cm mark A 60-N downward force at the 0-cm mark (the left end of the stick).Explanation / Answer
Weight of box W = 3*10 = 30 N
A force has to be applied in such a way so that net torque is 0.
torque due to box,
M1 = 30*0.5 = 15N*m (downword)
torque created by another force should be equal to 15 N*m.
which in only posible for option D.
75*(0.70 - 0.50) = 15 N*m
so, the Answer is 75 N upward force at 70 cm mark.