Answer to Question #168403 in Physics for Andu

Question

6. On a body, which has a axis of rotation, act two pairs of forces, one right with value M1 = + 50 Nm and the other left with value M2 = - 20 Nm. a) Calculate the resultant moment. b) Can this body be in balance? Why ? c) If the body is not in equilibrium, in what direction will it rotate, in that of the right or left moment?

Answer 1

(a) Let's calculate the resultant moment:

$$M_{net}=M_1+M_2=50\ N\cdot m+(-20\ N\cdot m)=30\ N\cdot m.$$

(b) If the body is in balance the momenta must be equal to each other. But, the body isn't in equilibrium because $M_1 \ne M_2.$

(c) The resultant moment has the sign plus which means that the body will rotate in the direction of the right moment.