Question

Sir Lancelot rides on a bridge which is supported at one end with a vertical cable that can hold maximum tension of 5.80 times 10^3 N. The bridge has mass 200 kg and its center of gravity is at its center. Lancelot, his armor and horse together have a combined mass of 620 kg. Will the cable break before Lancelot reaches the other end of the bridge? If so, how far from castle end of the bridge will the center of gravity of horse plus rider be when the cable breaks?

Answer 1

here,

maximum tension , T = 5800 N

mass of bridge , m1 = 200 kg

combined mass of horse and Lancelot ,m2 = 620 kg

let he rides x m before the cable breakes

then equating the moment of force about the pivot

T * 12 - m1 * g * 12/2 - m2 * g * x = 0

5800 * 12 - 200 * 9.81 * 6 - 620 * 9.81 * x = 0

x = 9.5 m

yes the cable breaks when he travels 9.5 m from the castle