Question

Calculate the total torque (magnitude and direction) for each of the following cases shown below. You can assume the "bar" the masses are attached to is massless. The top point of the triangle represents the pivot point for the system. Be sure to include the magnitude and the direction

Here m₁ = m₂ = 7 g and d₁ = 10 cm and d₂ = 1.3 m

(a) Here m = 7 g and d = 10 cm.

Answer 1

For the first diagram we have

m1 = m2 = 7 g = 0.007 kg

d1 = 10 cm = 0.1 m

d2 = 1.3 m

Total torque, τ = (m1g)d1 + (m2g)d2

                          = (0.007 * 9.8)0.1 + (0.007 * 9.8)1.3

                          = 0.09604 N m

For the second diagram we have

m = 7 g = 0.007 kg

d = 10 cm = 0.1 m

The torque, τ = mgd = 0.007 * 9.8 * 0.1 = 0.00686 N m